Sure, happy to help.
I don't know exactly how long it took, but I'd say maybe 5 hours, give or take. I think just using Oshawott/Dewott/Samurott makes things pretty easy.
It seems like it takes a while, maybe, but I really think it's the most reliable way to do things. You'd have to play through once to get to that point, anyway, and you might end up spending 5 hours trying to RNG the roamer and never get anywhere, so I think it's better to just reset the game and RNG the IDs once you know you'll get what you want.