I just finished installing a set of the H9 (Robart # PT19HA9) struts on my GP PT19. Very easy conversion and very clean setup (took about 30 min., and I work slow). The H9 and GP both have 5mm landing gear wire so they fit perfectly. Be careful, the Dynaflite has 1/4" legs. I don't think you could make them fit correctly. Another consideration is the weight of the planes. The Dynaflite weigh about 16 lbs, the H9 about 13 and my GP 10. I talked to the guys at Robart and they think the H9 springs will be ok, but if they're too stiff I can get softer replacements from them. I also went to 4" Robart wheels. I've always thought the GP's 3.5" wheels looked too small and the H9's 5" looked WAY too big. I'll let you know how they work after the weekend, with pictures.