What is the "highest and best" application these can be put towards?
This is really best answered by saying... wherever they fit and work. I'm sure there must be stronger ceramics around today, but stronger isn't always better. The "dance" between the arm and the magnets is one thing, but what a racer prefers in terms of performance so he/she can drive the car the way they like is another.
The Mura Red Dots and Blue Dots were no doubt mostly used in full can-type motors, and they could work well all the way up to big wire arms, just as earlier longer magnets that were no stronger did. They sure worked well with tamer winds also, and have a modern thin tip, pretty much as thin as you could have and still use U-clips to install them.
As to length, magnets had already gotten shorter before these were a thing and arms from .440" to .460" long were the target, but no doubt people also installed shorter arms in setups with these magnets and they probably worked just fine.
I know also that, as the older longer magnets became scarcer (see Steve Okeefe's "Vintage-style" thread), these and other similar magnets were installed in Green cans and other similar early C-cans with longer (say .500"-ish long) arms. Would they "work"?, sure.
For a strap motor using ceramics, best to say that, if the motor is sized for "C" type magnets and armatures, the Blue Dots would work fine for many winds, but with gauss down because of the "can" being mostly gone, it might be better to look at what current similarly-sized magnets are available that might be stronger. Then too, an even shorter magnet could save you a little weight if you're looking to shave a hundredth of a second off your lap times.
Last, look at the thickness of the magnet and how easy it will be to get to your target hole. You can always hone a too-thick magnet, but shimming can be a PITA in a strap, although that's less likely to be necessary.
That's all I got!