The easiest brake master cylinder upgrade without needing to change the brake booster or bend the brake lines for non-ABS EG Civics with a stock 13/16" master cylinder (possibly also for vehicles with stock 7/8" master cylinder). The 15/16" upgrade master cylinder is specifically from the 90-91 Civic EX sedan. The part number for the upgrade master cylinder is 46100-SH4-A11 .
The master cylinder is the same for left-hand-drive and right-hand-drive Civics. If unsure, you can compare the orientation of the brake lines on your master cylinder, to the ones in this video or in photographs for the Civic EX master cylinder.
