Re: 6.5 wildcat
6.5/300WSM is very popular. In fact, so popular that Lee now makes limited Production dies for it and this wildcat could only be a few years old.
Performance will be in the same league as the 6.5 Rem mag of old. A good high speed puppy that will be toasty on your throats.
The STW will certainly up the vel a bit but barrel life could be very limited.
Depends on what you want to do. If going for all out speed - go big, go home. If looking for a LR rig for hunting/varminting, the 6.5-284 or RSAUM or '06/Gibbs/AI would all work well. The WSM just gives you 100 to 200fps more poop. You could always get a long barrel and pick up the vel without increasing the barrel wear.
If 1000yd match shooting, the smaller cases like my Mystic, 6.5X55 and AI versions will also work just fine.