I've tried it. Didn't get on with it. What I got on a bit better with was running a 2 point through a single shoulder strap. It was more comfortable but limited my ability to hot switch shoulders.
I'll grab that as I spotted the selector plate as a weak point on mine. Saves me modelling it up myself. I eliminated the ambi selector as it never worked anyway.
I use an LPVO and prefer low mounts for it. I use a half face balaclava with a mesh insert most of the time or a soft sided mesh mask for a bit more protection so that I can get as low down as possible.
Maybe look at the Silverback Tac-41 instead of the SRS. Essentially the same system but in a more traditional layout. It's just over your budget and that's without any extras though at around £365 new. I'm yet to see any turn up second hand. The only complaint I've seen so far is that the BB retainer sometimes breaks but it's an easy enough thing to fix and I believe some places or offering replacement or improved parts foc. There are plenty of upgrades available but frankly it performs incredibly stock. Plus the mag placement is more realistic for those of use who hate fiddling with vsr mags