Happy to help! I don't even have a pocket but I remembered seeing this online so now needing a pocket file is kind of a solved issue. I never liked having to export a separate proprietary format for a gameboy game because roms are such a nice clean universal format. It was like needing a different power cord in every country you go to.
Unfortunately to my knowledge that patcher only works for games that have had patches hand-made for each game, so it's not able to patch games that aren't on it's list.
The fact that it covers more than a thousand games is due, among other contributors, to how absurdly prolific JoseJX was at making patches (~1184).