IT WORKS!
Yesterday I tried out my invention- the “Paine DVT”, for the first time. They work splendidly! They consist of long fiberglass battens that extend all the way from the leech to the foot of the jib. Just as predicted, they prevent the jib-boom lifting and spilling wind from the upper parts of the jib. When you let the jibsheet out, the jib goes OUT, not UP as is the case without the DVT.