The big thing is getting the old ethylene glycol out of your system, trace amounts of water will boil out over time.
I don't know that you
have to plug your weep hole, but I'd do that anyway in the case of the Cobra. (no matter what coolant I was running)
The cap mod is easy, snap the back flow button off the bottom, you now have a zero psi cap.
Amsoil also makes a poly propylene glycol based coolant (as well as most "safe" coolants) that's about the same $.
BTW there's also a track safe version of the Evens, but it has to be replaced every couple years.