Between me and a buddy we have used the following: AlumiHyde II (good finish but bubbled off the barrel after firing several mags), Brownells Teflon Moly (I liked it but it scratches easily without doing it over parkerizing, but the OD is a puke color YUK!), Gun Coat (strong finish and has been my favorite), DuraCoat (another one I like as it is easy to apply and if done over parkerizing is very strong).
As to at home park kits, don't know. My Dad made a nice stainless tank we do all ours in.