someone used to make a little clip on funnel that snapped on the top of a quart oil can. I am still looking at the auto parts store for it again. had them when I was a kid. maybe I will try Jc whitney.

What I did is take an old two stroke oil bottle and the overflow goes in that and sealed since there is usually 12oz leftover from 5 gals. I am mixing 4oz/gal or 32:1 for wren per the manual.