Hi
Spraying is a frustrating problem...and one that even neutered males will do (some folks aren't aware of this). Here are some hints and I'm sure a repeat of some advice you've received:

-rule out urinary tract infection

-use a blacklight to pinpoint the areas that are sprayed

-use a good cleaner like nature's miracle or a mixture of 1/2 white vinegar and water to scrub and clean thoroughly

-apply feliway (bought at the petsmart/petco/drsfostersmith.com) and follow directions. Initially you will use this 6 times a day and then gradually lighten up.

-spend extra time one- on-one with him and do not add any more pets to the family. The moving could have even started this..or the smell in this new house (we can't smell like a cat)..or even an outdoor stray.

-ask your vet about prescribing medications if this continues and start over at the top along with the meds.

He thanks you for keeping him. Many pet owners give them animal up due to this...stressing them more...and causing them to spray even more..not easy to find a home for them in that case,