The sight arrived today, and I am happy to report that the sight will indeed work on a Henry H001 and H001T, albeit with a few very minor modifications.
1) When folded down, the elevation knob may contact the stock, depending on how far up the tang the sight is mounted.
For my test fitting, I used the front hole that had already been drilled/tapped for my Marbles sight, but the sight can probably be moved 1/4 inch further up the tang without interference from the bolt. This might give the clearance necessary for the sight to be folded all the way down. Alternately, the knob could be filed down to be a bit shorter.
2) The sight is just a hair off being perpendicular to the bore (it goes just a little too far forward). This can be fixed by shimming the site post just above the screw that attaches the post to the base. I'll probably use some adhesive aluminum tape as shim material (yes, it's that close to being perfect already).
3) The sight base is just a bit wider than the Marbles base, but it does not require modification to the stock.
4) The vernier on the side is hard to read because the numbers aren't painted. I'm going to try to remedy this with a paint pen.
I'm going to order a new polished receiver cover and have this sight mounted on it.
For guys with 22 mags you will enjoy the ability to sight in at longer ranges without running out of adjustment.
Other notes:
Windage adjustments are fairly pointless, and not really repeatable. The windage screws (yes, there are two) need to be loosed and the center post screw also needs to be loosened in order to effect windage adjustments according to the design of the sight. The windage screws lean the sight in one direction or the other.
You need to loosen the aperture in order to make elevation adjustments. I have min loosened enough to make adjustments, but not so loose as to make it easy to move out of adjustment. A side effect of loosening the aperture is that you can also make windage adjustments by moving the aperture from side to side.
Despite all the little quirks I've mentioned above, this sight is a real bargin at $55, and is $30 cheaper than a Marbles. Here are some side-by-side pics (the Marbles sight is the shortest of the two):


