Minnflyer's videos are great! I use a pair of needle nose pliars with balsa Epoxied to the tips. Wing tips are more about stretching than shrinking. Slow and sure.... Use sand bags to hold the wing down, gloved hand with pull tool. I always use my heat gun first on wing tips then once stretched, a good iron around the edge. Botton wing first then top. Trim even with the opposite surface.