This is big! you mention 30% bonus exp, do you know if this data is with the fillers being level 1 or 12-14 being mention?
Having to do multiple thousand runs less makes it more managable.
the 30% is static and per party member regardless of booster/killer lvl as long as the party members are within exp range and alive
where it gets complicated is how the exp is split
individual party member lvl divided by sum of party members lvl is the base exp split then you can add on the shrine bonus to whoever has one
obviously 7x lvl 1 boosters are going to net the killer more overall exp than 7x lvl 30s because their lvl is contributing far less to the sum of the party ==> a lvl 91 killer is getting (91/98) ~ 93% of the exp vs (91/301) 30%
maxroll has an exp calc you can use but theres no classic values to give exact numbers on exp per diablo kill
you can still see the relative value of boosting with it tho