As someone who has spent the last 2 months and probably 100 attempts learning how not to deep water start, I can say that I never could figure out how to get up on a big shaped ski. I'll give an overview of my experience and what I thought helped and hurt during the process of learning the deep start. For reference, I'm big and old (6'3", 260 lbs, 34). I learned at DFW Ski behind a 2007 Nautique 196 on a 69" 2017 HO Freeride.
The hands down most critical piece of learning was the deep-v training handle. In fact, I haven't even tried starting with a standard handle yet since I went to DFW Ski. I'll transition to it at some point, but for now I have no reason to. It gives me that much less to worry about.
Second, was lots of quality 2 ski starts. My biggest problem after skiing most of my life self-taught on combo skis was letting my butt go backwards and front knee be straight. It was really counter intuitive to me to let my ankles and knees roll forward to keep my mass forward on the ski. I just couldn't get it for whatever reason. After enough 2 ski starts, I finally figured it out, and that's a critical component of success.
Third, was getting the rope higher. I am starting from a tower. After a few more starts I'll transition to a lower rope attachment point and see how much difference that really makes, but as I recall from my early attempts it was a big help. Even if the pull angle didn't make any difference, it helped give me a point to really focus on. Look up, get up. That was a hard thing for me to master. I looked down or to the side I don't even know how many times without even realizing it. I had to really put all of my focus on looking at the rope attachment point and let the rest of it kinda happen around me. That was a game changer.
The problem I had trying the wide shaped ski was that it would want to wiggle during the planing process. Alan told me that's normal for a shaped ski to want to do that, and I never could really figure it out. Honestly, we didn't waste much time trying, but that wiggle, that was weird. My HO Freeride doesn't do that at all at any point during the start even with only 1 foot in the ski.
Things finally start clicking for me dragging a leg. Honestly, I could probably figure out a 2 feet in start now that I have the feel of letting my body roll forward on the ski and standing up, but dragging a leg is really clicking for me right now. I went 6/6 this morning on deep water starts, and it feels really good to be skiing instead of falling.
Getting back to your question, a shaped ski might be fine or it might just be awkward like it was for me as it tried to plane out of the water. Maybe it wouldn't do that for someone with better technique or a smaller size than me. What did help was the deep-v handle, practicing quality 2 ski starts (when I get it right, it is a million times easier getting up), high mounting point on the rope if for no other reason than a spot to focus on, and dragging a leg (though that might not be an issue for smaller folks without a gut and 260 lbs to work around).
I hope this helps. It's a hard thing to master. Much harder than I thought when I decided this summer I was going to learn how to do it :smile: