For sharpening the electrodes I would recommend chem sharp. It is cheap and works well.
http://www.ebay.com/itm/321001600815
I got mine for $9 + Shipping. They turned down 8.25... might want to make an offer at $8.50?
As for the tungsten, I also use 2% lan for AC and DC. Works great. I would say get 1/16 and 3/32. That will cover 99% of what you will probably need.