Saddle on the Miyata is sloping down. This throws weight to handlebars and means the rider will always be pushing on 'bars to get back up on the saddle. Looks more to me like need for a simple saddle adjustment than an occasion to rebuild the bike. Consider that the likely best height for the saddle is where the nose of saddle is now. Bring the back of the saddle down.

Saddles should be level. More than a tiny variation from level is an indication of a problem. Or a source of all sorts of problems.