I agree and the rubber works nicely. This one is just meant for backpacking in and shooting in mountainous terrain for training. This isn't a dedicated "range" setup at all. I think for the application it should work great. I made myself a full second unit at well, to replace my heavy steel unit that sucks to climb up mountains with.Good design, the weight reduction is awesome. I'll be interested to see how the aluminum frames holds up to spall. From a guy who's shot a lot of steel, and helped out at a handful of matches, I've seen my fair share of target failures. The thin low grade turnbuckes are gonna get tore up fast. Appears you'll need something more substantial connecting the turnbuckes to the plates themselves.
The most durable lighter weight connection I've found is rubber strapping. It's got woven fibers in it, connect with 1/2" grade 8 bolts with large washers, washers and nylok nuts on the back, put strap on back side of plate. I have a dual rack with a 4" and 6" plates I shoot positional practice with my prs rigs 6mm/25/6.5s heavy for cal, 2700-2900mv. That target has taken prob 3k plus rounds of fire, and one the straps finally failed 3 weeks ago, and it failed cuz the bolt came lose. I simply cut 2" off the strap, drilled a new hole, in strap, and tightened it all back up, and banged on.