A 100% 1st PC pattern.
ILSZ has 22 minimal solutions.
When you place an O on the furthest right, you have a 92.26% (1550/1680) chance of achieving a perfect clear. However if you have an O as your 1st, 2nd, or 3rd piece of your second bag, you will have a 100% chance of achieving a perfect clear.
This field has 33 solutions which you can find here.
From the above field, if you place J and O like below, your chance to do a perfect clear will be 58.33% (490/840).
This field has 15 solutions.
The following pattern is useful to know not only for ILSZ but also for perfect clears in general.
- knewjade's Best Chance Field