Just as a follow-up to this thread...a 10-amp "temporary" fuse held up fine for 4 days in the desert and 5 days' in normal driving activity around town (fridge stayed nice and cold). The DC plug stayed solidly in place with the Blue Sea DC socket.
I am disappointed that Engel USA never called me back after I left a VM 2 weeks ago though.
Thanks for the help and advice, guys.
TLCA # 14207