Rob, that is a great job.
When i first went into mason biz, i cut everything the old fashioned way with hand tools. that just took too long to meet competition, so i bought a cheapo circular saw and some abraisive type (carborundum) disc blades. i burned out the saw on the first job. For the next job, and the next, and so on, i kept trying other makes and burned them up very quickly. I finally stopped in to my supplier of rental machinery and told them my problem.
We talked for a while and they told me others were having the same problems and they did not like to rent out their "skill " saws for any type of mason work. (since most of their clientelle were masons, they must have had quite a lot of problem. Eventually, after many many visits, the help started referring to me as "The Non-Latin Mason" Some of my friends called me, and still do "Tinkerelli") :

i asked to look over all of their hand saws and we took every one down off the shelf and looked them over very carefully. If you look at almost every hand type circular saw, there is a sort of vent hole to cool the armature. that vent on all but one was right down beside the blade arbor. i determined that even tho a whole lot of dust became airborne, there was still a certain amount that would get sucked in to the armature.
We finally looked over the Milwaukee 8-1/4" and immediately, i decided that was the saw to get. It also had that vent hole, but it was way around at the far side of the armature and brushes. it was the most expensive "carpenters" saw they had but i had had my fill of loading up the landfill with the el cheapos. That saw eventually lasted for just over 30 years until it finally caught fire (from inside somewhere) and just burned up. I never used it for anything but solid masonry or "dirty" lumber that had been used for concrete forms or scaffolding. It cut all types of stone, brick, concrete and cinder blocks and lumber full of concrete and nails.
Another thing i always advise about cutting any masonry is to do as Rob is doing. Protect lungs and eyes. That masonry dust will get into everything plus places that aren't even things and you don't even know they've been invented yet. Dangerous stuff. I not only used face and eye protection, but usually set up a fan to blow the dust away before it could rise to my face.
I have said before within previous discussions, I would NOT use my Festool saw for any type of masonry cutting, no matter what sort of blade i was using. I seem to have a recollection that Festool will not honor their warrantee if the saw has been cutting masonry. That is not a direct quote, just something that settled among the dust in the back of my head. If i am wrong on this, my apologies to Festool; but if i were in the business, i would not warrantee any type of woodworking saw that was used for cutting masonry>>> period
Tinker