I averaged 15-20% outdoors on 60m and 30m I get half that. WRT comparing 30m vs 60m IBU, there is surprisingly little difference. Honestly, I think we're talking like 10-20% change. No need to resort to use ISO oil. WRT DMS; Our boiloff rates are HUGE compared to pros. They average 4% over 90m. That's the reason they boil so long, they HAVE to.