Mine's completed
Hi Ron,
To answer your question first, my mouse hole looks like it's probably the same size as the original other one.
Now I'll add some additional info:
I was contacted off-list about another concern that I also saw and had. With the RV-10, there were no lightening holes in the fork, so drilling that hole for the bolt that serves as an anti-rotation bolt, was tougher. I drilled mine in an area less likely to weaken anything. That causes one issue, however. If you look at the pics I'll attach to this post, later the nose wheel fairing goes over that hole that I drilled. I didn't want to also put the hole into the fairing bracket if I could avoid it.
Seeing as though the whole purpose of that bolt is to prevent rotation of the axle, there are 2 things you can do. I called matco and both are acceptable. #1, you can just not drill that hole. The beauty of the axle design is that you can properly torque the main axle bolt, and really, if you have that tightened down, the axle won't rotate anyway, it will rotate only the wheel, and not the bearings either. So that is what would be my choice, had I thought of it at the time.
#2, if yo notice my pictures, I took a bolt that would nearly bottom out, cut the head off, slotted it, and used it as a threaded stud that would stick out just enough to keep it from rotating on the axle. Since there are 2 spacers on the axle, and you can remove them, this stud was short enough that I could just pull the opposite spacer and still pull the wheel off. That studd still prevents rotation. To prevent it from coming out, I used loctite on the thread. Now my fairing bracket can fit right over top of the hole. That bolt will now never have to be removed. I would have just left it out, but I may as well use it since I drilled the hole.
Finally, check out the picture of my final valve cap clearance from the fork. This is with the Matco axle, and the proper 511.25 rim. It is plenty of clearance, and there is no way the stem will ever contact the fork. So the end result is good.