Clark as I recall I had my Huma at 100 bar for my 177/
250 barrel. I did pick up at 177/350 barrel but haven't tried it yet. Moved this fall and can't find my tuning notes and haven't had much time to shoot.
What I liked about my tune at the time was that just by changing from the 177/250 barrel and the 22/350 barrel it was like two totally different guns. Just below the point of being twitchy in 22/350 but then a soft shooting plinker for my boys in 177/250. With the shouldering effect from transfer port to 177 barrel there are pretty significant changes in power when switching between 177 and any of the larger calibers.
In fact I started my tune in 22/350 using the chart below. I believe you have or had a 22/350 barrel so maybe this chart will help. If you still have that barrel you could try some of these tunes in 22/350 and see if there is one that takes you to the edge of your comfort zone. Then swap in the 177/350 barrel and see how it shoots, shot count, etc.
You'd probably need the chronograph working to tune the HST at the caliber change. I did. However, maybe it wouldn't be as big of deal when switching calibers but not length. The good news is that once figured out the HST clicks have been repeatable, at least for me.
I should note that I don't have a reg tester and the bar settings on my Huma sticker didn't quite match up to the results in the chart below. But I still found the chart useful as a starting point in tuning.
I know this isn't what you asked for but I wanted to mention it since I recall you having that 22 barrel. Maybe it will help, or at least give you a starting point. To me it made sense to start tuning in the larger caliber and work my way backwards.
I believe this chart was created by Jack.K.