The larger reservoir is for the front disc's, because they need more fluid pushed to them. Somewhere "down-stream" from the regulating/proportioning valve should be a block that splits the brake pipes for the front brakes. That's normally the easiest place to plumb the line-lock into the system. Most of the popular solenoids have two outlet fittings so they will work without too much effort. If that's not the case, an adjustable proportioning valve can be installed.
And BTW - there are NO stupid questions!!
Lew