modified tork lift

I`d hate to see how windy it would have to be to blow a pop-up of a truck :)
You already drilled a hole , but what was on a 04 Outfitter I had was instead of front eyes or hoops , they put a 3/8" TEE NUT /with a washer on the other side and 2 links of chain in between , and used that with a longer bolt on the lowest of the three jack bolts , so you hooked the turnbuckle to the link of chain

The turnbuckles are designed to provide 300 lbs. of force to hold down the camper. With cross winds only the turnbuckles on one side are resisting the force. A side force from wind is going to only need to overcome 600 lbs of force of the two turnbuckles on one side of the camper to have a problem.

With a wind speed of 35 MPH and gusts of 50 MPH, not uncommon in many parts of the country, the side load on the camper is going to be at least 900 lbs.
And it is a leveraged force with the camper sitting several feet off the ground and with the load not on solid ground but a truck bed with the flexing of the springs and the tires.

It is really surprising that this is not a more common problem.