I have a TS and have done trigger-work, grips and some frame modifications myself for a very modest price. I experimented with the Czechmate-based thumb-rest:
But found the Shooting Sports Innovations NITRO FIN Tanfoglio/CZ Slide Lock Thumb Rest:
worked better for smaller handed folks. It required some minor fitting to function 100%
I've handled a TSO and liked it but, believe the TS is a better value for me.