You just have to measure the stepover height just like any other bike. These bikes are great for short or short-legged people. I got a Terry style bike for my 5'1" wife.
As to 24" (ISO 520) tires, you can easily find Panaracer or Kenda 24X1 tires (25mm). 24X1 1/8 (28mm) Panaracers also exist but are hard to find. You can also find 24X1 1/4 (32mm) from .... Terry, where else:
https://www.terrybicycles.com/Tellus...x-1-1-4-32-520
My wife's bike is running 24x1 1/8 (28mm) Vee Speedster:
https://www.ebay.com/itm/115509958205
In reality, even 25mm tires ride well enough for bantam weight Terry-sized riders.