I've used both
With either, you could use a plastic putty knife to take off the large residues, and then use paper towels to wipe off the rest. However, with the Napier, it is so easy (and gratifing) to just hose it off. Seeing you are in NY, do you not have access to a hose? I'd use real caution with spraying off the other stuff if it hasn't been wiped down first - the non-Napier BURNS real easy (as in your skin - don't ask me how I know!), and I really wouldn't want it sprayed on to me! I think most people wipe or scrape it off first, then hose off any remaining residue.
I found the Napier worked great on the aluminum, on my Argosy, it didn't work so well on the galvanized steel - I had to use the other for this part.