Pentode Power Tubes - Ultralinear vs Triode

Thanks for chiming in. Like so many other things, it seems the devil's in the details. Someday I'll know better than to think I can come up with a simple rule of thumb without more exceptions than rule.
I suppose when you start getting into tube rolling and mode of operation the changes are subtle enough that everything else has as much or more influence. I'm surprised no one has mentioned changing modes with different cables yet.

KT77 were already next on my list of tubes to try. I got the 7581A because a lot of their described attributes were also appealing to me, and they are about $100/set cheaper than the KT77. For my speakers and listening habits I definitely don't need more power and I don't feel I'm missing any punch. I keep trying things and muddling through because "You can't get what you want, till you know what you want."

@atmasphere always nice to get answers from an expert. They never really covered vacuum tubes in the few EE courses required for an ME degree, and those are only a faint memory. From further reading I gathered that the ratio of the screen-grid and plate can vary quite a bit to find the sweet spot in ultralinear and would be dependent on the tube type. So with tube rolling on an amp like mine (Primaluna DPHP) would running in triode mode be more consistent when comparing different tube types?

What about tube life? Hypothetically, if you adjusted for the same output voltage, would one mode be significantly harder on the tube than the other?