I've used turbulators on two models in the past. In both cases they had airfoils designed more for speed than for floating. In both cases they became very "sink-y" when I tried to slow them down. I made turbulators using 1/8 inch wide automotive trim striping tape used two layers thick and the low speed range was greatly helped. If you can't find the automotive tape then you could use regular vinyl electrical tape cut down to 1/8 wide and use two layers again. One layer wasn't enough I found. It helped but not enough. 3 layers had no extra effect and the high speed portion seemed to be affected on the first model I tried them on.

So if your model seems to become draggy and sinky (very technical terms... ) then try some tape turbulators. Start with them about 30% back and move them forward until they help. If you get to about 1/4 inch from the leading edge and they have not helped then either your airfoil didn't need the help.

If your model uses a floaty airfoil then you may not notice any effect. Also on fast airfoils there will be a small penalty from the extra drag but it's very little and the low speed thermalling is so much better that the small loss of speed is not an issue.

Good luck.