So I have a few pairs of NOS F40T12 lamps that I would like run.

Unfortunately, I only have a "shop light" LOA fixture and I bought a new tandem 4' strip but it's ballast is basically a shoplight ballast, so I have heard this is not ideal to run F40 lamps, especially ones that I want to last as long as possible.

I am not knowledgeable about ballasts. I did go to HD and found electronic F40T12 ballast that would run nearly full current (650ma) with a pair of F40's. It is made by Advance in Mexico, are this OK to use with NOS F40's?

I also may have a pair of "Homebrite Gold Label" residential F40 ballasts that I removed from my 1990 built home, however I am not sure that these are REAL magnetic ballasts, they seem somewhat light (weight) for that.

What should I look for in a ballast I can either buy new or NOS on eBay for best compatibility with my f40's??

Forgot to mention, I intend to upgrade new 2 lamp F40 strips with better ballasts, so I already have the fixtures. (Not trying to upgrade the LOA, obviously!)

I would look for a NOS magnetic ballast, the electronic ones might fail early or makes the tubes not last as long.

I ended up buying NOS Advance R-2S40-TP Mark III ballasts, got 3 of them for $29.99 shipped. They drive the lamp at a full 430mA, so I should be good to go?

I would say those 80s and 90s advance ballast are garbage cause of there dry film cap problems.

I would go for universial 446 ballast


But those balllast u bought will do for general lighting
Those  mark 3 ballast cuts out cathode heating
 After lamp have started.  Can make cathode last longer

I just need these so I can run my F40 lamps on full power.

Curiously, I can still buy "F40T12" fixtures at HD (even though the ballast in them is not full power) and there is a good selection of F40T12 lamps, although most are high CRI, but all are still USA made.

So, is all of the current F40 bulb stock I am seeing these days currently out of production? I bought some GE F40T12BLB the other day, and I can't imagine GE is still actually manufacturing F40's in 2017. Even with Philips F40's, I reckon T12 production is stuck in USA, which means lower margins, and Philips can't be doing T12 production much longer??

Also, just bought some Philips F40T12 Daylight Deluxe lamps, 90CRI. They don't seem very blue like I remember "daylight" lamps being, is that just my mind playing tricks on me or does high CRI level out the "blueness" of daylight bulbs?

Over here, some Halophosphate /765 (/D) lamps indeed look bluer than Triphosphor /865 lamps. The difference appears to fade away a little as the Halo lamp ages

T12 never got banned here,  but  they shifted to triphosphor lamps.  Basically banned halo blended
Lamp for F40s and halophosphate for energy savers
But only few halolamps do pass CRI and lumen curve
That currently CWX and 5000k lamps

The Halophophate lamps for full power did get banned in summer of 1995.  That year i could not buy any daylight  F40Ds and F40DX have not came out yet
Only choice i had was F34D from sylvania
 From that point on we lost F40CW, F40WW, F40W
F40D.  Then 700 series replace them until 2012
We lost 700 series lamps  then summer of 2014 it hits
The 4 foot T8s as wel

The Advance ballasts should be fine, but you may want to test them to make sure they are really driving the lamps at full power.  If they're not, no big deal as long as you don't mind dimmer lamps.  They should work well if they're NOS, though I've heard some of the Mark IIIs had capacitor issues out of the box.  I'd agree with @funkybulb about the Universal/MagneTek 446s.  They seem to be less prone to cap issues, and overall tend to run lamps at a slightly higher current.  However, if the Mark IIIs are in good working order, the difference will be negligible.

I'm running the Mk3s right now. They are much brighter than the original ballasts, of course. The rinky dink ballasts my strips came with consumed 108 watts, but the lamps were dim, in fact my NOS Cool Green lamps wouldn't light in the middle. The Mk3s drive the CGs very brightly, I am pretty happy with them.

All 3 Mk3 ballasts are NOS, and they seem fairly old as the packaging seems more 80's than 90's to me. Not sure how to date ballasts.

One other unusual thing I noticed about these ballasts is that they are "Made in U.S.A." weird. Didn't know that was a thing

Most older Advance ballasts are easy to date. There will be three or four digits stamped somewhere on the back of the ballast--this is the month and year.

We have Habitat stores here, and some other building recyclers.

Very unfortunately, because I live in a progressive West coast area, most all of the good stuff was very aggressively removed in the 90's. The most "vintage" stuff I see at recycling/reuse centers might be those brass/glass fixtures from the 80's-90's, fluorescent troffers, etc. It is rare to find actual collectible stuff.

My wife and I are VERY interested in buying a very old home that is original (well, invisible upgrades like copper plumbing and romex wiring behind the walls would be OK) and we have looked at hundreds in the past 10 years. We have been shopping for 10 years now! There are a lot of older homes where we live, and most like quite good on the outside. But you get into the house and EVERY SINGLE ONE has had an early 2000's "flip-remodel" done to it, looks like a display of Home Depot products circa 2004 throughout the entire home. Not a single vintage item left on the interior, except maybe for doors. Vintage homes have some very strange door sizes and house flippers didn't want to incur the expense of trying to fit modern standardized doors or custom doors in, so you still see old doors with original hardware.