Would a car without a proportioning valve run a larger resivor to increase line pressure to the front? Totally Spitballin' here. Just wondering.... but yes, these people MAKE mistakes, and even sell crap that dont work. Knowingly....
Reservoir size has no bearing on line pressure. The reservoir is larger because the pistons in a disc brake system are larger than wheel cylinders and as the pads wear, the level of brake brake fluid can get too low if the reservoir is too small.
Only the bore diameter affects line pressure.
You ALWAYS want FRONT brakes that can lock on clean dry pavement, that's how you know that they're achieving maximum stopping power. They need to do so predictably. Then riding the edge of lockup (which is the point of minimum stopping distance) is up to the driver or, in later systems, the abs system.
You NEVER want the rears to lock before the fronts That results in a spinout.