I used to have an 8 foot practice table with nearly six inch pockets. I told my instructor I wanted to get them tightened up and he told me not to even think of that. The looser the pockets, the more balls you make. The more balls you make, the more you want to play. The more you play, the better and more confident you get.
This is too true. I now have a 9 foot GC with 3 7/8" pockets and I know what he was preaching. Some days I head downstairs after work to get my usual hour or so of practice and I can't seem to run three balls. After about two minutes of that crap I get pissed, throw the cover back on, and go do something else. I used to clobber the 9ball ghost but am now scared to even try it!
Practice tables should increase your confidence, not beat it out of you. Do yourself a favor and get one with at least 4 1/8" pockets.
Just my .02
-James