I don't think I'd put end plates on a 3d model. They would make the transition more difficult into stalled flight, rather than going thru it and staying there. Talking with Kyle, He feels that wing rock is more a function of cg than anything else. I would tend to agree with him, based on my own flight tests. A nose heavy ship is hard to force into a stall, whereas a tail heavy one wants to stall all the time. In a harrier, you want to be stalled completely, thus not leaning on the lift of the wing to hold the model up. Sure, there is still some lifting effect from the stalled wing, but the flow over the wing should be completely tubulent, and staying that way. For those interested in trying the tip plates, just be sure to change only one variable at a time, and test all flight conditions before and after mods to get a good comparison. My guess is that they will be like wheel fairings, they may help some things, maybe look cool, but not really worth the trouble.