Brake advice - master cylinder

[Project D]

Just in case, FC and FD calipers are the same mechanically speaking (the differences are only aesthetics) and the specs are very close to the original AE86 or SW20 calipers.
We are talking less than 10mm² of total piston(s) surface. (2027mm² for the AE86 vs 2036mm² for the RX7 and SW20 calipers)

One of my friend have FC calipers with the stock 13/16" BMC on is AE86 (zenki) and it work OK, but the pedal travel is a bit long.

PS: apparently not ALL SW20 turbo came with 15/16" BMC, some used 7/8".
If you want to go that way, here is a exemple of the 15/16 version:
http://www.ebay.co.uk/itm/282608737104