Best strategy to get to 300 from 250+

Hi, reaching 255 and can’t see myself spending another month playing daily (I play like 1h a day max) to get to 300. Reading the sub there’s a consensus that high level pits are the way to go for xp. Which level is the sweet spot? Been doing levels 105 because can do it quite fast with or without groups, but I’ll probably have to do like 500 of these. Whoever got to 300, what’s the secret besides self harm? Thanks!