What are you using to keep your back warm? If you don't have anything yet, the HH Supershelter + stock tarp attached as designed = dry in severe wind blown rain. At least the one or two times I have had it set up in those conditions. I actually think it is more wind and rain protection than a larger hex tarp tied to the trees- but with no SS- provides, unless it is a LOT larger maybe. At least more protection when you are actually in the hammock.
Of course, that still doesn't help if you need more dry space when you are not sleeping. And most folks prefer down UQs, which MUST be kept dry. And some need more privacy at least some times. And a fair number of folks don't like the SS, though it has it's few fans.
If you don't mind a few extra oz and spending some more money, there are some great tarps available. I have found the JRB rectangular 11x10 to provide GREAT coverage and stability in the wind. I thought the OES MacCat dlx was a work of art, at only a couple more oz than the stock tarp. But you still have to have a larger tarp pitched correctly for windy, stormy conditions. If the ends are not fairly close to closed on the windward side, wind can still blow rain onto the hammock/quilt and splash up from the ground can get you. I've seen it happen with a normal "A" frame pitch. It could have been easily prevented with a "storm" pitch, or by mostly closing the windward end, but I had not done that on that one occasion.
For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.