I'm in the process of fitting a DRO setup to a Myford Lathe using the same slides.
I'm using Shahe scales bought through AliExpress, I had no trouble with ordering and the slides arrived in 2 weeks.

**LINK**
I'll ditch the displays and will use TouchDRO on a tablet or mobile phone, see Yuris Toys, this has lots of options for setting up drilling patterns and plenty of tutorials online, There is an alternative screen for lathes.

**LINK**
This uses some interface hardware based on Arduino all described on his site and picked up on Ebay
All in the parts for a 2 axis kit were about £100. Fitting the cross slide scale will be the hard part, not too much room on an ML7. After Christmas there should be plenty of cheep used Android Tablets around to use as a screen, I'll look for a Tesco Hudl or a cheep chines clone they sell used about £20.
I'll post some pics when I get it up and running.
Regards
Peter