Seeking Advice about Replacement Nib

[cj2020]

Hello All,
I have a pen with a Jowo 6 steel fine nib. I find the nib to be super stiff and not the most comfortable to write with. Looking to switch out the nib. My questions are
1. Should I choose a Jowo 14 K or 18 K gold nib? Is there a difference in the writing experience?
2. I dislike European nibs that write too wet and put down too thick of a line. My fav pen has a Nakaya M nib. Do you recommend that I go with a F or an EF Jowo gold nib?
Forgot to mention- the pen only takes Jowo 6 nib unit.
Any advice is welcome.