Hey dude, I personally have a slingshot, but 95% of normal bench tm is pretty light in a slingshot, which can usually give you about 10% over your true 1RM. For instance my slingshot 1RM (last I did) was 140kg, my bench 1RM is 130 so if TM was up to 125kg after a couple cycles, 95% of that is only going to be 115 and I can probably get 10+ reps with that on a slingshot if I'm relatively fresh.
What I've tried is doing a your 95% set, then resting and doing a Last set Last with the slingshot which worked okay.
You could also look at finding your slingshot 1RM and doing a couple cycles with that as your bench press movement instead of standard bench if you're really keen to use one?
Its also really good to use if your shoulders are feeling dinged up
hope this helps at all