I've never owned a suppressed lever action but it makes all the sense in the world. Also never owned a Henry before. So I think it's time to check off both boxes.
But which caliber would you go with knowing you would be reloading for it?
38cal: I don't know what the heaviest is that will feed. MAYBE 200gr? Plus would be it would take less powder and lead so cheaper to shoot.
44cal: Not much sure what the advantage here would be over the other 2? 44 magnum is a beast but loud.
45cal: Can load a very heavy slug to send quiet. Can also match or get close to 44 magnum performance. But would take more powder and lead. However I have a ton of LPP and not many SPP.