just make the porridge thick
DS didn't take a spoon and missed having that as a option, especially when out and about.
DD wasn't messy at all, I didn't understand what everybody used to go on about and it seemed like all the spoon fed puree babies were far far messier, then DS came along.
Regarding mess after breakfast, we fed him in his nightclothes, then lay him on the bottom of the bath with the shower running. Took no time and certainly no longer than other methods. Lunch was a tricky one, but after dinner was straight into bed clothes so no extra change of clothes there. Lunch times I just generally replaced his top so also no biggie.
I've never pureed anything, but of course there are normal foods which are effectively puree's so a bit of spoon feeding, if they accept is great.
To be fair to other people saying that most people do a mix of finger and puree foods, most literature does only seem to have puree's in it and present the whole thing as some complicated scientific experiment.
Also I didn't start of with breakfast, just lunch and dinner and introduced breakfast later.