I merged your posts, since they are about the same thing.
The NEMA 17 motors you linked to have a 1.7A current draw, so they are right at the limit of working outright with the MP6500 and Tic T500, which can only handle 1.5A continuously without external cooling. Since you are able to control your motor, it seems like this has not been an issue for you, but if you run into any overheating issues, you might have to add a fan and heatsink to your Tic. However, at the point where you want to change your setup from using a Tic to a CNC board and a few stepper motor drivers, you might consider using our TB67S249FTG stepper motor driver carrier, which can handle 1.7A continuously. (Note that it does not have the same form factor as many of our other stepper motor drivers, so instead of plugging it in directly, you will probably have to manually wire it to your CNC control board.)
1 revolution per second seems pretty slow for how you are running that stepper motor. You might consider reading this forum post by Ben, which has tips for achieving faster step rates.
We do not have a driver that is powerful enough to handle the 2.8A current draw of that NEMA 23 stepper motor.
As for your other questions: yes, increasing your supply voltage from 19V to 36V will allow the current to rise quicker, which should allow your system to achieve a higher step rate. I suspect the advice you were told about limiting the power supply voltage is aimed at reducing the effect of voltage spikes, which get worse as the voltage increases. Adding a large electrolytic capacitor across power and ground on the stepper motor driver should mitigate the effect of those voltage spikes. (Our Tic stepper motor drivers already have a built-in capacitor for this purpose.)
By the way, from the pictures on the Amazon page for that kit, it looks like it uses knock-off versions of our DRV8825 drivers (they might not work the same as our boards).
-Jon