According to Baer Racing, the optimal front to rear bias in piston area is at minimum 60/40 or greater. If you are planning to run the "factory" front disc-single piston calipers, the front to rear ratio would be approx 55/45 (rough calculation) with the larger Lincoln brakes. Using the smaller rear calipers would increase the ratio to approx 65/35. I suppose that an adjustable prop valve would handle either scenario, but you might be closer to its maximum range with the larger rear brakes.
I look at it this way, the larger Lincoln rear brakes were designed to run with front calipers that had 3 1/4" pistons and a "hydroboost" system. You don't want to end up with the rear end doing most of the stopping.
I would also take a look into what size rear caliper pistons would be used on a Camaro with "factory" front discs and compare that to the two Lincoln options. I haven't checked into this setup, so I'm sorry I can't help there.
Here is a link to a very detailed thread that may be helpful https://www.camaros.net/forum/Forum7/HTML/000452.html
In the April 1998 issue of Popular Hotrodding, pg 86, there is an article that covers this rear end in detail. Toby, let me know if you can't find a copy, I could fax or mail one to you.
I would also listen to any advice Mr David Pozzi has to offer as well, he would definitely know better than I.........?
'68 Camaro base coupe
'92 Caprice wagon