Thank you for your suggestion. I have tried to match his results to your websites modals and clusters.

Modal 1: off by 1 at 16 sites, off by 2 at 2 sites. from 37 markers.
Modal R1b: off by 1 at 12 sites, off by 2 at 1 site, from 36 markers

The clusters he appears closest to are the NC-Henry S cluster represented by 8464 and unknown origin represented by 17684

TN: off by 1 at 5 sites, off by 2 at 1 site, from 20 markers
unknown: off by 1 at 4 sites, off by 2 at 1 site, from 21 markers

I've also run his matches through the Ancestry.com, ysearch, smfg, and familytreedna Strickland projects with no 100% match at all sites. Some of the marker searches have suggested a couple of other options, but I'd like to find another direct male descendant of the Frant, Sussex Strickland clan to compare to before going further with those results. So far, I've only run across researchers from daughter lines.