New to linuxcnc, basic question for DRO modes with encoded handwheels

The 7i96s  looses some inputs to run MPGs. I would go with a Mesa 7i76E or the EU version. It has two MPG inputs. Perhpas PCW will be able to add a third. With the 7i76E the machine will run as fast as you can wind the MPG. There is a parllel port example in the docs so its pretty easy to adapt to the mesa card as its just changing the pin names.

If you go the parallel port route, you will probably find you need to run at least two parallel ports. Encoder inputs can eat up a lot of input pins (3 axis would require 6 input pins.) But when you start to look at multiple parallel ports and buying add on parallel port cards, Mesa starts to look much more appealing. For example a Mesa 5i25/6i25 doesn't cost much more than a 2 port parallel port card, but is much more capable, and you know it is going to work with Linuxcnc, vs the crapshoot compatibility of buying a multi parallel port PCIe card. For example the last PCIe parallel port card I used only sort of half worked until I modified the breakout board by adding some external pull up resistors to some of the pins.