Mina,
FWIW, for my 7-ish" diameter cheddars, I work my way up to a final pressing of 300 lbs. That works out to around 7.5 psi. I could probably get by with less, maybe 200 lbs., by leaving it in the press longer.
Karlin's book is, unfortunately, somewhat infamous for mis-prints. In addition, I think her book may be the one that gives pressing "weights" in terms of psi (which may just get called pounds!) ... BUT what is really meant by "psi" is the amount of air pressure used for a pneumatic press. Unfortunately, there is no way to translate the air pressure into actual psi on the cheese without knowing the diameter of BOTH the cheese AND the pneumatic cylinder ... and the latter is omitted. Very, very confusing! (Again, not absolutely sure it is Karlin's book that does this, but I think it might be ...)
I'll be very interested to get pictures and taste test on your results! I've never tried making an alcohol-infused cheese before. Sounds like it could be a whiskey thing to do ... yes, pun intended!
Just saw your last post as I was finishing this one - I routinely age my cheddars in a vac bag - often for > 12 months. There can be a little seepage of whey (can also happen with wax), but if it happens I open the bag, wipe it out and dry the cheese, and re-seal. (Rarely have had to do that.)