Have you tried Roundcore Boomers, they are really nice and a lot more flexible. I think they last longer and not as “dark” as regular boomers.
Yes I have. 45-65-85-105 on my Jazz, 40-55-75-95 on my Precision and 45-65-80-100-126 on my Yamaha. I wouldn't say "a lot" more flexible as they're not quite as flexible as the Sunbeams, but comfortable, yes. They're also smoother in mids than the regular Boomers, as in less grit and grind.