So to flesh this out some more, and assuming 15g tallboy kettle, using just the ic3500:
You say you can't get a good boil going with 10g and w/o lid, but with lid it does well. Of course, it's not as difficult to maintain a boil as it is to get it going. So if we attempt to bring, say, 13g of wort up to boil from mash/sparge temp, with lid on, do you think that is possible? Is it possible to then take lid off at that point and continue a sufficient boil for 60-90 mins? Basically, is it possible to do 10g batches using this burner? I've read elsewhere that it is not, but I'm not convinced.