Got rank 5 MC about 2 days before the event ended and then just made the weapons I wanted and stopped. I'd like rank 1 but without 2x skill exp it's far too much for me if I can only use mats I gathered on my own. Still, during the event I got to rank 5 on purely my own mats, so I'm rather proud of that. Ranks 8 and 6 were mildly annoying, but I pushed through.
Also, although I'm too lazy to gather mats to make weapons to sell, I'm more than willing to craft the weapons on request for free, if you give me the mats. Nobody ever takes me up on that though, probably because everyone and their mother has r5 MC already.