There is no BIOS limit in the traditional way you mean it, because the Tandy has no BIOS. Besides that the XTIDE would handle the IDE detection and recognize pretty much any CF you throw at it.

Just get a card you can find for a fair price, say from 512MB to 4 or 8GB, but nothing too new to ensure compatibility. Often older/smaller cards are sold for more because "rare!!!111!1 vintage"
Then partition it according to your OS limitations: for DOS 3.3 create a couple of 32MB partitions, for 6.22 I believe the max partition size is 2GB.

so no data corruption or anything like that if I use like 2 or 4 gigs card with, say, DOS 2.11, which I think was the version the first tandy 1000s released with? and 32mb partitions is the max that can do too?

tandy do have bios, its just it has no options so you dont get "into" it.

you will need some form of xtide bios + cf card, and best to have small card that you can make < 32mb partitions. These systems work best with dos3. you can run dos5 but you dont really get any benefits.

I typically use 64MB cards with my Tandy 1000 computers. These are also running DOS 6.22.

I've found 64MB a good size for the types of games and software that run on a Tandy 1000.

I found a cheap local deal for two CF cards, 32 and 64 mb, both cisco branded. I hope these will do fine for testing at least. I wanna mount it and set it up now. I see the XT-CF-Lite 4.1 card has dip switches to set up I/O Addr and EEPROM Addr, apparently I should set them to addresses that do not conflict with other devices... However I have no idea about any of this, I don't know what addresses are taken by other devices or what are free, and I don't know how a conflict looks, so what the hell do I even set these to? They seem to currently be set to I/O of 0x300 and EEPROM of 0xD8000.... Are these fine?

The Tandy 1000 has 3 isa slots and all 3 are taken, one by a 256k memory expansion board, one by a mouse controller + clock/calendar board, and the last one by some sort of async serial port board thingy, I guess the last one is the least useful as I have no idea what I could possibly use that for, I'll take that one out to insert the XTCF there

P.S.