The thing I noticed the most is that sometimes it goes out of place and when I change the strings it tends to go all the way down
Ah, ok!! So, to answer your question 10-52 is a good string gauge to use for drop D tuning. That is also what ive used for awhile too!
However you will have to adjust the claw screws that hold the tremolo springs almost every time you change strings. EVEN between different tunings, for example I set my guitar up for dropped D. When i tune up to standard E tuning that is enough of a change to throw the trem out of parallel. I then have to adjust the claw screws about 1/2 turn clockwise...this increases the tension of the springs causing all your strings to go sharp, retuning will then drop the trem deck down slightly returning to parallel.
Since you have a custom-s there should be holes in your dust plate that allow access/adjustment to the screws with a long phillips head screw driver. It is ALOT of trial and error. Make sure your strings are properly stretched out before you attempt to level the deck of the tremolo. Adjust each screw equally in between tunings, i go 1/4 turn each time.
Let me know where this gets you, i love tinkering around with these things and am available for further assistance!