Fender Stratocaster Tremolo question?

So i recently got a new MIM Strat and got it set up professionally with heavier gauge strings. However, after stretching the strings and playing it for a few days, i still had a little bit of a tuning problem, so i replaced the three stock springs in the back with 4 new ones. I knew putting another spring would flatten the bridge down and stop making it float, which was ok with me. However i still want to do dive-bombs, and with 4 springs it's pretty stiff/hard (and im worried cuz it feels like im gonna break something when i use the bar). Got any advice on what i should do?