From my notebook: considering 1966-2023, considering different samples size suggests a prior of 20-30% for Beryl. Forecasted ACE (IVCN atrack + CSU current number) for Beryl is about ~33.47 (currently 27.7). Some stats: (Below chart probability is the number of storms with higher ACE divided by the number of years in the sample period.)

Number of storms in AL basin with ACE > 33.47 (since 1966): 30
Years with storms in AL basin having ACE > 33.47 (since 1966): [1966, 1967, 1971, 1979, 1980, 1989, 1995, 1996, 1998, 1999, 2000, 2003, 2004, 2005, 2007, 2008, 2010, 2016, 2017, 2018, 2019, 2021, 2023]
% of years having storms in AL basin having ACE > 33.47 (since 1966): 51.7 %

52% should be too low to give to Other considering the current climatology, so eyeballing the chart from the recent two decades, 20-30% looks reasonable.

(above chart, but only >=25 ACE):

It is believed this year will have abnormally intense hurricanes because of warmer SSTs and a warmer climate in general than in the past so it's hard to use the past years to judge this year. Having said that I would start by giving a prior of 70-80% to Other, and will consider the low end to be more likely, giving ~20% to Beryl having the top ACE for this year (on the low end considering how abnormal this year is).