The AI and TI masts share some common parts. The mast bases (hole version) are the same so the fit over the pin is the same.
The furler drums are different. The TI (lower mast in pic) is longer but has the same diameter which is why the mast retainer lever still works (just). There is no room for uplift play which may be an issue. You can see that the tapered section of the TI drum is longer and that is what is touching the AI's mast receiver bearings so there is a bit of extra play there as well. (see 3rd pic down in my previous post)
Yes it would be easier just to cut the TI mast a bit shorter and replace the mast base but then that would mean I couldn't use it in my TI.
If the initial on water test as is works OK the solution for me would be to
a) just add some tape to the drum taper to build it up that little extra
b)-slip a cut down AI furler drum (or similar) over the TI mast that would be removable. Something along the lines of the small sail adaptor I've made and yes I'd start another thread for that.
PS- I'm surprised none of you Hawaiian trail blazers have tried this yet!