Vinnie, I was only at the early learning stage with my English wheel before I decided to sell it, not enough room in my 9'x10' shed to work!!
I did a few courses and I'd suggest you do the same if you can find someone to teach you.
If you're getting stretch in two directions, then you might have too much pressure in the center of the wheel or the wrong shape bottom wheel. Rolling a single curve like to show is not easy from my own minimal experience.
It's trial and a lot of error until you figure out the pressure and direction you need to travel in to achieve the result you want. It's 90% feel.
Just for the heck of it, here are a few pics of some of my practice pieces. Far from good yet, but a start.
The best pieces I did were the the top and bottom wing tip panels for a Lancaster bomber restoration, but alas, not a flying aircraft.