The Dove end supports are a step in the right direction. They are only 5/16 bolts, but still the right direction. I have often considered using a bottom plate, like the HS pictured, and a countersunk 7/16 under the shaft for mounting. Also thought of larger shafts like that, with a .125 through hole for oil. Lots of ways to approach it. The main problem is the 3/8 bolts....and only four, are not enough for serious roller cam spring loads. The T&D has eight 7/16 holding the stand. I have had a total of two Dove super HD units....both somewhat mangled and stuffed in a box here someplace.
The single shaft T&D is not compatible with stock-size stuff. The Dove end support will only engage an extra length Dove shaft. He should not have put two sets of oil holes in those otherwise OK shafts.
I like the single shaft T&D for high lift flat tappet or hydraulic rollers. I lean more toward a bushed non adjustable with heavy shafts, studs, and end supports for streetable hydraulic rollers. That works very well up to 400-425 open, with no bearings, no adjusters, and no roller tip to fail. Good for 2-300 more rpm than aftermarket stuff that has more inertia weight.