Do not attempt to use HAT L6se in small sealed enclosures. They are designed for infinite baffle (or at very minimum LARGE enclosures). You will not get the response you are looking for there. Either cut vents to allow them to breathe to outside, or choose a different driver for that application.

Another option to consider for sub is the Dayton HO10 or HO12. Both are quite good in (very small) ported enclosures.