machine seal surface on kingpin spindle to match ID of D44 spindle. Press D44 Spindle on then drill and tab knuckle or just weld that sucker on.
I've seen a 2.5 hub setup that was done this way. ID of snout was machined to press fit onto the seal surface of stock spindle. Then another piece was machined for end of the stock spindle to fit inside 2.5 snout. then everything was welded up.
Trying to stay away from the machined snout block idea unless the same snout block would work with ProAm snouts as this is only a "temporary" solution. Welding the snout on it one option but not sure how the stock caliper would line up and redoing that for a willwood caliper is getting away from the point of this setup.