1.8 ratio rollers for exhaust?? 063 heads

Ok so rather than call my machinist cuz he’s sick of it I’m sure lol I came to this site haahaa I just had knee surgery so I’ve got entirely too much time on my hands .... I’m running 063 heads on my 460 bbc not sure of the exact ccs but I assume they’ve been milled at least twice I heard 101 ccs stock I got some flatties w valve reliefs and an xe274 flat hydro so it’s a dual profile cam 284 on exhaust and .005 extra lift now the question I saw a flow bench data sheet at 28 inches and exhaust flow @.6 to .700 is in the high 160s cfmThat leaves my flow percentage at a measly 64 percent ewwww so I know they try to cover the gap there in percentage w extra duration but what’s the formula in that what gain I’m tricking that hole into?? Also would I benefit from running 1.8s on my exhaust valve for a little extra flow???? What do u guys think??? My cr at 100ccs and a .036 gasket gives on paper 9.35ish