I'm a newbie relatively speaking to most people here, but I had to relearn my starts when I switched to two boots. I always started with my foot in the RTP so I didn't think it'd be much different, but it really was. It might depend on how you're starting now, but with the RTP I kept the ski out in front of me a little more and didn't realize how much I was flexing my heel on starts. I had a couple failures after I put the double boots on, and a few 'harder than normal' starts after that, but it didn't take too long for starts to be as easy as before. Just ball up a bit more and keep the ski up towards the butt crack if you aren't already.