I think you're asking if you can use shocks sized for for stud top mount with the procomp adapter...if I'm understanding that right then I have two answers to that question: "it depends" and "I wouldn't".
The easy out is to say "It depends" "on your specific setup". If you're at the right height then it may not make a difference.
In the suspension setup that I'm running on my Tahoe, "I wouldn't". To be more specific, my front stock shock ride height is 13 1/8" (13.125). If I swap them with coliover QA1's and use atomic's lower shocks the shock ride height is reduced by 1.75" due to the dimensions of his lower shock adapter (it's not a bad thing, just a statement of fact
). For my setup it would not be good to also use the procomp adapter due to 1) the dimensions of the QA1 shocks I plan on using and 2) my ride height. I plan on going with the ds303's which have a recommended ride height betweem 10 3/4" and 11 1/4". If you subtract 1.75" from 13.125" then my ride height should be 11.375"...which is within the ds303's range of ride height. If you were to also run the procomp adapters then you would need to account for their height too (1.5"):
13.125" - 1.75" - 1.5" = 9.875"
If you look at the specifications of the shocks on
QA1's site then you'll see that the ds303 has a compressed length of 9.5". That's only 0.25" of travel before the shock bottoms out...which should equate to about 1" of travel at your wheel. 1" of wheel travel before the shock bottoms out is not something that I am comfortable with.