I'm in the midst of my first flooring install, glue-down over on-grade slab. Going with Shaw's Pebble Hill Hickory 3" and 5" planks over 1360 sqft. My old flooring was saltillo over 2" of mortar. I've removed it all and am now going through the pains of subfloor prep, which is giving me trouble.

First off, after chipping out all the mortar, I found many more or less large holes in the slab, the most extreme being ~3" deep x 6" wide. I've purchased Bostik's SL-150 UL to screed the floor. Should I just mix this with gravel and float the holes? Is their a less costly alternative?

Also, there are ridges in the concrete slab encircling most rooms, about a 1" rise from "level". My grinder doesn't deal with them and my chipping hammer, although seemingly the best option at the moment, doesn't seem adequate either. I can pulverize them with the hammer, but I've made little progress with this approach. Any suggestions for dealing with these problem areas?

Much respect to you for doing this absurdly laborious job, and thanks for your advice.

Sounds like a job for a pro with lots of prep experience to me. I'd have to see it to tell ya what to do. I do consulting if your local and actually do the prep for peoples.