Strength: 0.6-0.8
Keywords: UPDATED 8/19: I seem to gen the best results with: hud_h1tchh1ker, road, street, mountain, hand on hip, outstretched arm, blue sky, day, thumbs up, hitchhiking, from side, spread legs
hud_h1tchh1ker, on the side of the road, hand on hip, outstretched arm, blue sky, day, thumbs up, suitcase (or backpack)
Other Misc Trained: upper body, full body, from side, from behind, ass, cowboy shot, sitting, standing, hitchhiking, desert, mountain, holding sign, motor vehicle, ground vehicle, car
you can remove "hand on hip" but the chances of getting 2 thumbs up increases
Also try "one outstretched arm" , could help avoid the double arm thumbs up
you can also try "standing on sidewalk" , it might discourage middle of the road gens