Those kinds of walls/fences are pretty common in the SW U.S.A., and they do have fairly high h/t ratios. Apparently, the design philosophy is basically that people don’t live near or under them and if/when they fall over they just fall in someone’s back yard. The self-weight and prevailing winds are not great or the real problem, but I’d worry about wind gusts and EQ’s. One of the biggest problems is that they act like dams in rains w.r.t. water back-up behind them and they can scour out under the found. Many Metro areas and Counties have a sort-of preapproved design and details and a tabulation of h/t’s and panel lengths, etc. They’ve been around (some designs and details) for a long time, have proven themselves over that time and are kinda grandfathered in, without exactly meeting todays codes. Generally, they consist of pilasters/posts every 8-10’, which are reinforced and grout filled. Then, the infill panels are only 4 or 6” thick, 8x16” conc. blk., with bed joints mortared and reinforced with ladder type joint reinforcing. The head joints are not mortared, they are just laid loose against each other, and the pilaster blocks are “H” shaped so the panel blocks fit into them on each side of the pilaster. The founds. can be as simple as a trench with drilled deeper holes at the pilasters, and then the whole trench filled with concrete or even flowable fill. In your case, the difference btwn. 8 and 10” conc. blk. should be that big a deal when labor and all else is considered.