Re: Brass issue
You will probably want to start with standard 300 Wby Mag brass (though you could use 300 H&H as well), and just neck it down to accept 6.5mm bullets. Normally, when going this far down, you'll want to do this in steps, probably using an intermediary die or two. That is, neck the cases down to say, 7mm, relube and then take them down to 6.5mm in a second step. Some of the more involved wildcats will call for special forming dies that provide these intermediate steps, but I can't say for sure on this one without doing a little digging. After the case necks have been reduced to accept the new caliber of bullets, the brass gets fire formed in the chamber, and you're done. From that point on out, it's no different than loading any other cartridge.
There's plenty of articles on this process, as well as some things written in the various manuals, that should make all this pretty clear. Just takes a little digging, but you shouldn't have any trouble in turning these up. There've been a couple books done on on case reforming specifically that would be a help here, but they may be a bit more than you really need. Pricey, too. Give it a shot with what I've described so far, and let us know if there's anything more you need.