Phil, There has been some discussion about wood masts that may help …
As you suggest the weight should be off the pin, and support the mast at the deck level – both laterally and forward – so you have a snug fit.
I don’t see much point in using removable chocks to control movement/bend as in a metal mast if you have a gap.
I guess that wood shims all round are all you need for the mast to be snug with the deck. And set these with rig tension on.
I suspect the rig would have been tensioned with bottle screws – rather than a tension device on the genoa halyard.
David Smethurst has some pictures of W48 that may help;
You could ask him to email originals to you for more detail.