Variable hydraulic lifters for 440 engine

I have adjustable roller rockers so i can make the adjustments.
Although, I am leaning more towards the variable lifters to be honest.
They really provide the reduced duration where the engine needs it, and restore to full lift right after the TC flash rpm, as AJ mentioned to me.
That should really throw in everything she's got at the right time and in the meanwhile can rumble along at low rpm.
In the email from Rhoads they did not mention to me the height of the lifter.
Maybe one of you guys who used them know?
How much difference could i get away with? My adjuster screws are on the high side with the smallest safe amount of adjustment and as long as possible push rods so i can go down if these lifters are shorter.
But if they are higher that would be a problem.
Guess they need to be adjusted down though, as in the instructions it say's you need to screw the lifter piston all the way down first.