Were adjustments to your lasts needed? And if yes, did the adjustments further improve their fit?
michael, it's been a while.
generally, i prefer a loose fit on all of my shoes and like you, i have an high instep.
the first two pairs(vintage 1994) are still in service and going strong. the last has been changed in the meantime. actually it is not an improvement in fit but in appearance. the changes are minor but steady.
i didn't have to many rtw at that time, due to fitting issues. now, i am set.
meanwhile i have a sweet spot for shoe restorings. so either rtw or custom made. all of them get fitted after my pattern and it works, at least for me.
again, i love the good news about your project with cliff.