good luck with printing 618 with any head. That stuff is NOT user friendly.

Warps like an amoeba being tickled, soaks water up like silica gel and really requires a sealed, heated chamber. Which - if you've got the creator pro - you do have.

The stock flashforge nozzle and extruder is absolutely fine. Not sure why you're trying to fix something that isn't broken.

And you don't actually need to print nylon at the top end of the temp range.

I have made a few sucessful prints with 618 at 250, but only quite small items are succesful without major warping.

I've got a roll of taulman bridge that I haven't got round to trying yet. Hopefully that's abit more user friendly.

I haven't found anything my stock extruders can't handle yet. From nylon, through all the flexible filaments to wood and bamboo fill.

The only issues are with the filament itself. But the extruders have so far handled every kind of filament without any issues.