Hey DS
As I understand it the guitar neck / nut in your Yamaha pacifica is too narrow for your taste? You would like a wider nut. If so then You're probably in luck
Warmoth makes nuts in the following widths 41mm, 42mm, 43mm, 44mm, 48mm. So one of those should suit you.
https://warmoth.com/guitar-neck-nut-width
Nut Widths
1-5/8" (41mm) - Narrow
This is the smallest nut width. It is very comfortable for fingering chords and playing rhythm.
1.650" (42mm) - Vintage Medium
This width is considered "vintage" spec. It is very comfortable for fingering chords and playing rhythm.
1-11/16" (43mm) - Modern Medium
This is the standard nut width. It is our most popular nut width size, and the closest to modern Fender® necks.
1-3/4" (44mm) - Wide
This slightly wider nut width increases string spacing and facilitates lead playing and string bending. Players with large hands or a background in acoustic guitar may also appreciate this nut width.
1-7/8" (48mm) - Superwide
Players with large hands or a background in classical guitar will appreciate this nut width. Superwide nut width is only available on Modern Construction necks.
Next question is. Does the body of your yamaha have a regular industry spec (ie Fender) cutout for the neck pocket? Ultimately you have to unbolt the neck to confirm these measurements but you can a hint by just measuring the assembled guitar where the body and neck meet.
https://warmoth.com/guitar-neck-fit
Also avoid using the word "thin" when referring to the nut width. The guitar world seems to use the word thin when referring to the thickness of the neck between the fretting fingers & the thumb. Nuts are referred to as either "Wide" or "Narrow".
Hope this helped
