I went from a Connelly Concept (94) to a 67"D3 Nomad and went from being stuck at 2-3@28 off to running it back to back on the first set on the Nomad. I am about 200lb as well, my next ski was a 68 Nomad rcx and then a used 67" X7. I felt the same as you on other brands, could turn them but not accelerate through the wakes.
I have skied on Quests, Fusion, both Helixs and the Arc. I think you should try a newer D3 as well as they just seem so user friendly straight up. I think my favourite was probably the X7 but the new Arc certainly felt very good. There are a lot of D3's around here and they have a reputation for skiing well straight up, other brands obviously ski well too but seem to take longer to adapt too and more setting up.
That's my two bobs worth. Good luck
You asked whether the Quest was more a 36 ski than say an X7.
I don't think any were designed to be a slower speed ski than another. I think @skibrain would confirm that.