How large was your hex? Was it an 11 ft (long) tarp and an 11 ft hammock, hung so the ends were about 9 ft apart, giving you a 1 ft overlap at the ends?
Orientation to the wind matters. Were you broadside to the wind or parallel? Though parallel seems just wrong, "... the wind will blow right through ..." it also presents the smallest area to the wind, and there is a partial blockage because of the tree supports. And some tarps have "doors" - extra nylon on the ends that can be folded in to close off that portion. You can also angle your trap so the end facing the wind is lower than the other. And you can hand your rain jacket, wet side out, at that end as a wind/rain block.
Another "block" against rain whipped underneath is to use an underquilt protector (UQP). Vendors used to sell them in waterproof or breathable materials but I believe they have mostly stopped using non-breathable materials because of condensation issues. That means the UQP is not waterproof, but it will keep those occasional raindrops off your UQ because it hangs loosely around it.
