Those are nice models as of themselves but too mechanical looking for the purpose proposed IMHO. I'm rather rooting for the Mongoose Arachnid Cliff Mites, myself... Them or the Spider Bugs, but the latter will almost certainly be quite too large.

As an aside, I've been prepping my old Vor Shard Crawlers to stand in for Phase Spiders until the Mites come out (or in case I happen to be short on funds when they do), but as usual the work progresses very slowly...