How forceful should I be?

It may be setting your sites too high to expect him to really stand down during nesting season. I'm lucky that my hand raised Pilgrim Gander doesn't go after me, but my swans do. I carry a large stick to block advances, which might work better with swans than geese considering that swans tend to hit you with the wing. I also don't bother putting the food next to the nest, The females really should get up off the nest anyhow to keep up their muscle strength. Would it help to keep the the food near the entrance of the enclosure to minimize contact?

 

I've also put my kiddie pools so the kids can fill them from the outside of the fence with the hose . . . I agree -- all my ganders are just grumpy, and I have one that is a menace. I've heard though that the first breeding season is the worst, and they calm down some in following years.