Are you new to reloading? The 7x64 is an easy cartridge to load, but there isn't a huge amount of published data in North America for it. It works well with slower powders- 4350 or 4831 would be my first and second choices. Most rifles give their best accuracy with heavier bullets- 160 to 175 grains.
If you can't find data for the powder you have, you can use the start data for the dimensionally and ballistically similar .280 Remington, and work up a safe load from there. The 7x64 will have a much longer throat than the .280, so you should expect lower pressures and velocities than for the .280 with the same load. Conversely, you can expect to hit high pressure with higher loads than same. Make sense?
Lee dies are reasonably priced, and work as well as most in my experience, and Tradeex have brass available.
Hope this helps.