Yes, the OP seems to be thinking four days off grid is equivalent to living on Mars, but we can help him with that. Actually he is thinking ahead to more time off grid after that. He is in denial about big inverters, but his DW will sort him out on that :)
Yes, there is a debate on just what it means for when you need a 20 amp circuit to run chargers and converters. It turns on the idea of portables (15a ok) vs permanent (it runs longer than x hours at a time) which needs 20a under USA rules. (No idea what Can rules are on that)
Last I heard a while ago, PowerMax is looking at that issue, where their PF corrected higher amp portable ADJ models (15a plugs) designed for car showroom work are now being used as converters. They might have to offer a choice of 15 or 20a plugs on them when you order one to comply with the rules. They were seeking clarification from the inspectors on that when I was asking about it after I got my Kill-A-Watt and saw some of the VAs.