My guitar is setup for 10-52. Would I be able to put 9-42 strings on it and adjust the back trem cavity and it would be fine? Or would I need a full setup?
Would be fine. but the action is going to be higher.
if you set it up then yeah, otherwise i guess your neck would go "U"
I can change the springs and screws in the back of the trem and I can adjust the action myself. Is that fine?
smaller strings = less tension = less neck relief = LOWER action. probably too low if you had it low before and the intonation will be a little thrown off especially on the heavier strings. after the switch adjust the tremolo and let the neck settle for a few days. if you can feel or hear any undesirable changes in action or intonation the adjustments should be minor (no truss rod dramatics).