This is one of those areas in TIG welding that beginners or inexperienced people put WAY too much thought and worry into.
Tungsten type, tip prep, grinding wheel and so on matters very little until you get enough experience to see any noticeable difference.
Get some 2% lanthanated or ceriated tungsten. Pick whichever is cheaper at your LWS. Start with 3/32". Grind a point on it. Any old point. As long or as short as you want. Weld. If it gets dirty, grind it again. Grind it on anything you have handy. Bench grinder, belt sander, angle grinder, it DOES NOT MATTER. Just weld with what you have.
Once you get a few hundred hours of seat time behind a TIG torch, you can start to see the SUBTLE differences in between the alloys, the tip grind angles, when its more or less appropriate to use one or the other, and why.