From wiki
Main Article: ST Stacking
[edit] Two Columns Wide
Two columns wide bases do not have the modular flexibility of three columns wide bases. They, however, provide more room to stack the field. The simplicity of required tetrominos in the setups also makes them easy to learn.
[edit] Three Columns Wide
Unlike the two columns method, three columns wide bases have the advantage of modular cores. A player can opt for a different core to accomodate an unfavorable preview. Although the player has less room to stack the field, tetromino dependence is minimized. I tetrominos are also not needed to fill in leftover gaps.
[edit] Alternatives
ST L Start
For two column wide ST bases, an L start may be desired if an L comes early in preview order. An L start will also fill in the first leftover gap created by the S tetromino. Note that the notch for the L start is one row lower than that of an S start.
After performing four T-Spin Doubles using an ST base and plugging the leftover gap with an I, a player can use the L Start base in place of an S base. Note that the notch for the L base is one row lower than that of an S base.
