Like most I like to tinker around with things on the bike as I look to get better and learn more about correct body position on the bike, and despite owning an older ( read shorter WB) long travel full sus, I like to think I’ve done okay optimising it so far.. Bar roll I see mentioned a lot but haven’t actually experimented with it yet.. any things to look out for as to the effects of making adjustments?

FWIW I’m running a 780mm 38mm Renthal Fatbar and a 40 mm stem and its currently more or less positioned with the rise vertically at the moment. any tips?

Try it a bit forwards, try the levers around a bit…

In that respect it probably depends a lot on your back/torso length, wrist flex, hands etc

With a high rise bar it’s also like increasing or decreasing stem length as you tilt it.

Loosen the clamp bolts off and sit on the bike in your normal riding position. Close your eyes and rotate the bars until it feels like your hands and wrists are in a natural position. Retighten the clamp bolts and try riding. I find it most comfortable with the bars drooping down slightly, others don’t like that. It’s a matter of personal preference.

Yeah that’s not great if you want to set the bars for a standing position though

I like it rolled back from vertical.
Just mark where you have it now and change it one way then the other. Easy and fast to do, and nothing to lose.

Yeah that’s not great if you want to set the bars for a standing position though

you mean, the way i have it now? more or less vertical?

Just lean the bike against something or ask a friend to support it.

https://www.vitalmtb.com/features/Vital-MTB-How-To-Cockpit-Set-Up,1490

As a starting point I like the rise of the bar to be in a line parallel to that of the forks.

It always feels most comfortable to me that way and then it’s slight adjustments of brake lever and shifter until everything feels right.