As you add weight to the front of the arrow, you decrease the spine. What I would do is to shoot a bare shaft to see what the effect of increasing your point weight would be. If your shaft is flying perfectly with a 125 grain point, we would expect it to fly nock left (for a RH shooter) if we increased the point weight to 290 grains. If we wanted a 650 grain arrow, which I think is a pretty good weight for your setup, we would have to do one of these things:
1. Use a stiffer shaft
2. Use a shorter arrow
3. Add part of the weight to the back of the shaft with an insert, or throughout the shaft with a weight tube (this stiffens the shaft, but I don't know how you would do this with a wooden arrow)
On the other hand, maybe it isn't flying perfectly with a 125 grain point, and maybe it will fly better with a 290 grain point. You'll only know if you shoot a bare shaft.
Moving to 10 gpp should improve the performance of the bow if the arrow is well tuned. It will make the performance worse if the spine is too weak for your bow. Better performance, in this case, means a quieter bow, with better penetration. The trade-off is that it won't shoot quite as fast. Most hunters are willing to make that trade-off, at least up to 10 gpp, some even go higher. Most target shooters are looking to maximize arrow speed, so would shoot a lighter arrow. But with a 65# bow, I would guess you mainly want to hunt with it.