If you don't get good chip removal in aluminum you can get a slight over bore. I'm not a machinist, but the mechanics in our shop encounter issues like this if the tooling doesn't provide adequate chip clearance.

Another thing we use for bushing installation is liquid nitrogen, probably not necessary in your application, but cooling the bushing in your freezer may help with the installation.

The progress so far is great, the welded area looks seamless in the pictures; I was anticipating some discoloring, but it looks perfect.