I have a 105 gallon rimless tank and have 4 mp40s. I have them running on a mix of reef crest, tidal swell and constant mode. I'd like to throw some short pulse mode in there but I'm worried about damaging my tank from the wave motion.
I wouldn't worry about it if all the pumps aren't synchronized because you won't get any real wave action that way. Sounds like the way you have them set up you are just looking for really randomized flow. If you synced all of them and ran all them in short pulse it would be a different story all together.
I would have reservations in doing it in any rimless tank fully synced imo. That's alot of water that is moving back and forth and there is nothing but silicone keeping it together. If you only have 2 on that and the other 2 on something else you won't get any real synced waves. You could try it and see what the water does.