Josh,
My answer is based first on the fact that I don't live in Alaska or someplace that regularly gets strong, sustained winds (plus the fact that my J3 is kept in a hanger - of sorts). Since you asked about tying down a J3, I've read up on what the U S Government thought shoud be done with the military J3, the L4.
In both the Flight Handbook for the L4 (1943, revised 1953) and the Erection and Maintneance Instructions for the L4 (1943, revised 1951), in both drawings and the written description they say tail INTO the wind, tailspring tied to an anchor driven into the ground with the exposed portion pointing away from the tail. The wings are to be tied to anchors driven into the ground with the exposed portion pointing to the front of the plane.
The instructions clearly show to tie the
rear stick using the lap belt from the front seat.
That's what Uncle Sam said. But of course they weren't working from prepared fields with permenint tiedowns!
I'd suggest, if you tiedown at an airport with permenint tiedowns, try to get one that is protected from the wind by hangers or nearby trees. Tie securly (NO slack in the ropes or chains) and use external gust locks.
Your information doesn't show where you are located, but if it's REALLY windy, I think spoilers can help keep the plane from trying to fly on the tiedowns. Good quality ropes or chain, doubled if necessary never hurts. If it is REALLY, REALLY windy there have been many Cubs tied down with the tail into the wind that have had their REAR lift struts fail due to the wind pressing down on the trailing side of the wing. There were pictures posted on here at one time.
John Scott