Intriguing ! I think one of the most telling things was that you had difficulty in entering the tappets into their bores . Maybe someone has been there before , and after all , your reason for starting the job was to correct a previous error
The 7 lb persuader may not have helped
Good luck with the reassembly ; will you be rebuilding what you have or fitting any new parts whist you have it off ? My reason for dismantling my heads was to replace the valve stem oil seals and stop the blue smoke on startup .