Older Tushingham masts were more flex-top in 460+ SDM. Any Tushingham mast will be old as they closed in 2016.
www.unifiber.net/masts-selector-v2014-2I wouldnt go for one of those.
I've used Simmer SDM in Ezzy sails, Lions and Cheetahs and they performed fine. Being slightly more flextop than Ezzy meant the leech at the very top of the sail was too loose, but hardly noticeable in use. Those masts were from 2009.
Exocet/XO sails were made at the same place as Simmer, so I would guess masts also at the same place and specs as Simmer masts. One of XO freeride sails and a foil sail was the same as a Simmer as they collaborated a bit. Same with a couple of Exocet and I99 boards.
I've also rigged on Duotone and they looked fine, although I didnt actually sail with it. I was just comparing masts before I bought Ezzy in 2016.