If disc is on the sideline, a isolated FOS cut is more effective because the FOS defender might be able to poach any cuts from the back of stack.
If a reset happens instead of a under cut, #1 should clear to the stack IF the opponents are playing a Handler Force Middle defense. Cuts from the back can happen as continuation.
Standard back of stack cuts into the open side is valid as well.
However, note that if you see that FOS player making a move, clear off immediately to avoid clogging. The FOS may be moving because a reset is necessary.
Standard vertical play continuation is very important to avoid a super heavy handler play.