I've decided to go with FLATWOUNDS! I have some questions though...

Chromes are rather zingy for flats, especially right away. They may not yield the tone you are looking for.

I played 2 Fretless Fenders last weekend and both had, I assume, fender flats. Nice strings, nice tone. Nothing spectacular but nice tone. Keep in mind every idjit and his brothers dog could have been messing with these basses as they were floor models...

I am unclear on string through bridges, but I do not see why not.

As to all being stainless steel? I cannot say.

 

The only flats that I know of that will string-through without breaking are TI's, at least in my experience. Labellas have a warning on their package about it, don't know about the other brands you mention.

 

Also consider DR High Beam Flats - they may be brighter than you are looking for, but everyone seems to love them.

 

You should add Labella Deep Talkin Flats to your list. Contrary to the packaging - they're fine in a string-thru.

 

Labellas will give you THE classic flatwound sound. And they get better with age. I only top-load mine these days, but years ago I had some thru-body for a good many months on a P and never had a problem. BUT, I have seen them and other flats start to "come-apart" on the bridge saddle (usually the low E, or B) on other folks' basses. Never heard of one breaking though, but when you see the wrap starting to pull apart it can't ultimately be a good thing . . .

 

EB Flats have a bit of clank to them. I second the Labella suggestion. The Labellas are warm and deep. They last forever. And you can go several different gauges.