Microshift has come up in the world. Chances are very good that if there is a 100% price difference between the Micro-shift and Sunrace thumbies it is not simply because the Microshift has friction mode as an option. Obviously this does not mean that the Sunrace shifters are beneath contempt. Microshift once occupied that market niche. Not everyone has $80 to drop on a set of thumbies. You are in a perfect position to do a direct A/B comparison and give us a report. Good luck.
P.S. I would not have removed triggers to put on thumbies for any reason. I might (and have) remove grip shifters and replace them with ultra-cheap friction thumbies but that's me.