My tip is unfortunately something that is unavailable. I've got a mk1 continuum in .22, and I used to shoot heavy slugs with the 700mm/slug A barrel @65fpe, but I decided after some time to convert it into a 500mm superior barrel. Reason being that I didn't see the need for heavy slugs anymore. I shoot in wooded areas, and there's little if any wind. All reports and measured results from the superior liners showed that not only were they not pellet picky, they were not slug picky either. And even seemed to be less tune sensative.
I don't know when or if they will ever be in stock, but I would recommend getting a carbon tube from Earnest Rowe's custom shop. The tube is intended to be bonded to the liner to stiffen, and also quell harmonic vibration. That's how mine is, and as far as I can tell, it doesn't seem to care what I throw at it. Or how. Any and every projectile I've put thru it have given outstanding results. With severel different levels of power up to 50fpe. I havn't shot anything heavier than 25gr, though I do have heavier. I know the barrel isn't intended for anything above medium weight slugs.
But to answer your question on reg pressure. I would say that 135 bar might be good. But everyone's gauges differ. So, no one can really say. The best way to dial it in is going to be to really find peak power output of the gun, and then start backing off either hammer weight or hammer tension, or both until the gun calms down. You can listen to the report and tell when the gun is operating efficiently.
After you've found peak power output, when using a chronograph while backing off of the hammer weight/tension, you should see a very consistent velocity plateau before velocity starts to drop sharply again. It's best to adjust hammer toward the middle/back of the plateau, so we know the hammer is opening the valve JUST enough to make some serious power. It's not over-striking, or over-lifting. So, the gun should be very tame, quiet, and efficient here. That will lend to some very nice harmonics.
