WOW, that is way overpriced. Plus it looks like the outer stems are nothing but long brass truck stems that have been bent. And, as another person said, forget rotation. You'd have to pay to have the stems removed and installed and then rebalance, I don't think so.
I installed standard metal valve stems in all of my wheels and then used the V2B caps, these are commonly called alligator valve caps. They are the fleet standard for FedEx, UPS and evey major trucking fleet. This guys kit has them on the end of each valve stem. With my set up, nothing has to be changed around when I rotate tires.
Brass truck stems usually sell for $5-6 bucks, the caps are $1-2 dollars. You should be able to get your truck set up with installation for well under $100. 00.
I can check my tires very quickly, yes I have to use a dual head air gauge and air chuck, but its a safer set up than this guys kit. The reason he wants you to locktite the nuts is that the design of the stem along with the length will cause it to loosen with time and then leak. Plus those inner stems are way too long to be unsupported like he suggests.