okay, i never use the things. howevah, i got a new strat friday. upon changing from 9's to 10's, i had the same problem i usually do where the bridge raises up at the back. i was changing one string at a time. instead of having the bridge blocked like my other strat, i put 2 more springs in the back. problem solved.
finally my question. i'd really like to experiment with the tremolo bar so i'm glad i didn't get it blocked. is it still safe to do with the extra springs? i won't be doing any dive-bombing, just some subtle stuff. stupid question i know but i don't want to mess this beauty up. being the idiot i am, i've lost my sales reciept so until i can get a copy, i have no warranty.
thanx everyone

Hi jeebus: a couple of things. It is fine to use the whammy; you ain't going to do any damage, regardless how many springs you have.

However, adding springs to bring the back of the trem plate down is not the best way to go, unless you are looking for a stiffer, harder action on your vibrato. Better would have been to adjust the two screws that hold the spring claw to far end of the spring cavity, screwing them in to put tension on the springs. You just drive them in gradually till the back of the trem plate has come down to the height you want it - about 1/8" to 1/4" gap is considered right for a floating trem. (Jeff Beck goes for somewhere around the higher setting, so's he can bend up a full step or more. Most of us settle for the 1/8" measurement.)

Another thing: after changing between 9s and 10s you will have to reintonate the guitar by adjusting the saddles to make the speaking length of the strings longer or shorter. Otherwise they will play out of tune as you fret further up the neck.

It's all contained in Fender's setup guide, which probably came with the guitar or which you can find on this website.

Good luck - C

well, i did both till it got back where i thought it should be. i don't mind the vibrato being stiffer since i probably won't get crazy with it.
i'm still wary about intonation. i've read all the info and have tried both successfilly and unsuccessfully to set up guitars. it's actaully very good right now but i'll give it a shot if i'm not happy. the action is superb and i really don't want to mess that up.
as always, thanx for the response. i love this guitar.