Raymarine location - LOL. Well, I wouldn't put it there, but it might just be good enough. I don't think you can expect much of a performance increase by moving it unless the Raymarine reports a really substantial "corrected deviation" in the calibration menu, like over 8% as even in a perfect location it is lacking compared to the Precision 9 or its Raymarine equivalent (EV2 was it ?).
Bill provided pictures of the perfect spot to put your compass. There is a challenge, however. Keep in mind, with a fluxgate compass the signal in the wire is not digital and can be interfered with by radio's etc. So for example if you are tempted to extend the Raymarine wire to that perfect location Bill photographed in the forward birth, you don't want to run the wire past large DC wires, your DC panel, VHF radio, stereo radio, refrigerator, etc. on the way to the forward birth.
Battery wires are particularly bad as they are not "twisted pair", a configuration useful for canceling out magnetic fields that can turn back into electrical fields on wires that run along their length.
I experienced my prior Beneteau with Raymarine autopilot changing course 3+ degrees every time the refrigerator cycled, just because the fluxgate sensor wire ran past a one foot length of battery wire, then having the compass heading being affected by electric current by the refrigerator on the other side of the boat. Every other electrical device on the boat having the same effect.
The higher precision compasses are a joy to have, they can help your instruments do a better job of providing you situational awareness, as I wrote here on Panbo.
https://www.panbo.com/airmar-h2183-impr ... raymarine/
Until you choose to purchase one, check out your corrected deviation that appears in the compass calibration menu, and if under 8%, choose another improvement project for your J/109. And if over 8%, maybe you can find another location within a couple of feet that is much easier to move it too then the bow. As bottom line, the Raymarine electronics are pretty good at taking what it learns from turning your boat in a circle, and applying it to the imperfect measurements of your fluxgate compass.
Cheers
dan