Pinwheel

Pinwheel is a TSS → TSD → PC opener created by Winterfrost. In the first bag you only need Z before S and I, and O before L. It can be built 55.16% of the time with mirrors and 32.22% of the time on one side.

1st Bag
This is the preferred way to stack the 1st bag.

A skim variation can be used if the above setup can't be built.

2nd Bag
The main path for the second bag can always be stacked and has a 95.95% chance of achieving an 8-Line perfect clear, with the two most common solves being able to score a Tetris as well.

If you have a late Z piece, rotate clockwise, softdrop and rotate counter-clockwise twice to get it in place, as shown below.

This field is quite clean and flexible, allowing for a multitude of freestyle follow-up options.

8-Height Perfect Clear
This field has a 95.95% chance of achieving a perfect clear. There are only 9 minimal solutions, however due to the TS/Z you technically only need to memorize 6 different solutions.

Alternate 2nd Bags
These setups can always be used in place of the main path and give higher chances to perfect clear, but require more memorization due to having to solve two different fields.

This setup requires L to come before O to be used and has a 100% perfect clear chance with 11 minimals.

If you get O before L you can build this setup. It has a 99.80% perfect clear chance with 7 minimals though you also need S to come before L or Z if you're playing a game without 180 rotations.

Perfect Clear After 14 Lines
You can go for this after the L before O 2nd bag.

This can be stacked a majority of the time, however there is a fallback that has a 100% build rate with 180 rotations and a 78.85% chance to achieve a perfect clear for when this cannot be stacked.

This field has a 100% perfect clear rate with only 3 minimal solutions, with each one being able to give you a Tetris.

Although this can always be stacked with 180 rotations, certain queues will need a lot of waiting for gravity. If J comes before O you could potentially save time by switching to an alternate build.

This field has a 78.85% chance to perfect clear with only 4 solutions.

J Before and After O
You only need the first two setups to cover all bags.

Perfect Clear After 14 Lines
J before O:

This field has a 99.68% chance of achieving a 14 line perfect clear with only 4 solutions. Just knowing the first solve puts it at a 95% chance. The first and third solutions can score a Tetris as well.

O before J, Variant 1:

This field has a 73.61% chance of achieving a 14 line perfect clear with only 4 solutions. Each one has the possibility of scoring a Tetris.

Double Triple Double
Discovered by mLurker. This bag can be stacked this way almost every time. It sends the same amount of garbage as Stickspin, although it requires a lot of soft drops.