Ms. T-spins STD is a Japanese opener created by Sasa.
It was also separately discovered by yamcrunchy in October of 2022.
The setup rate of the first bag is 72.54% when counting mirrored.
You can always stack the second bag this way, but it will often require the use of Softdropping.
You have a 41.67% chance of getting a Perfect Clear. Both solutions are shown below, and the O, Z, I and J pieces are in a fixed place.
In the second bag by holding your J piece, you can increase your PC chance to 56.43%, making you able to PC more than half the time with 7 solutions total.
Third bag and beyond
These are all continuations found in the original Ms. T-spin's STD fumen.
With both of the paths shown, you are able to complete a TSD every time.
Path 1 - L before O
Skim STSD -> PC
This STSD isn't as preferable as you will need to skim a line with the Z piece, getting rid of your Back-To-Back chain.
The likelihood of you not having any garbage is very low.
After completing the first TSD in the STSD, you have a 99.40% PC chance with 6 minimals.
Path 2 - O before L
You can stack this every bag with softdrop.