I did an optimization with data from September (I think) onwards trying SL's from 25 to 115 if I remember correctly, and an SL of 115 (112) gave the best results. The next best result was 40 which is what I have used ever since. The SL levels are not taken out of a hat and set by chance. For example an SL of 110 had much worse results than 115 and 30 was no good while 40 was ok. Obviously past results are no proof for the future but it's a good indication since the
FAPT team set the SL levels before October and their SL still proves the best.
If you search the forum for SL optimization you'll find my results thread. I use 40 because I am more comfortable with that even if it means my over all profit is lower than by leaving SL at 112. Up to you and you might want to re-do the optimization and see if Feb-March has altered what's most profitable.