I'm at the same point on the 47xx, a pump and zero means of affixing. Mine (Finney7) has a long slot in the bottom, I think you're supposed to fit it to the underside of the footplate and then cut a slot in the front end to allow the rod to go up inside the slot when the footplate is fitted.
In that instance mine would be too high so some sort of bracket will need to be forthcoming to lower it a mm or so.
Regarding Heathers conundrum, I think I would of cut the stub extension arm off the cross head and retained the cylinder blobby bit at the top, then soldered a replacement extension arm from scrap metal to the rear of the crosshead....but longer, then refitted the round blobby bit back on top.
Bit of a faff but the piston rod would of then been much higher.
Anyway, keep at it, it is coming along nicely
if everything fails then shout some Viking at it, doesn't fix anything, just makes you feel better