Originally Posted by FWAAA

I'd call right now and buy-up to an E+ aisle seat as insurance against not having an opportunity to buy-up to biz class at checkin. E+ would be bearable but E- would be painful.

Then, at checkin, inquire about a buy-up to biz. Several hundred dollars well spent, IMO (especially compared to the price of full C class, which the OP has already seen). If available, then great! If not, at least you'd have an aisle seat in E+.