Now the valvetrain.... Arghhhh!!!

I am guessing that the pushrods you have are for a solid cam with adjustable rockers. Comp also make a shorter pushrod (7.23 inches) that is made to be used with hydraulic lifters when using adjustable rocker arms. They will have a ball end for the lifter and a cup end for the rockers.
Part number for Comp is 7821-16. These should work fine with a hyd cam. Mopar also makes them, # P90006.

Standard rule for hydraulics is to take all the slack out of the adjuster then turn it 1 1/2 turns to set preload.