Your formal italic is way above average for the time you have been studying.
Foundational is an excellent choice for your next style.
Sheila's book has everything you need - except Sheila, in person.
When you say you have trouble with the round strokes - I am not sure what kind of trouble.
Generally, we have trouble when the natural quirks that we have developed in our everyday penmanship sneak into our lettering. My personal quirks are always lurking and will sneak in if I am not vigilant.
Slowing down is helpful.
Keeping a positive attitude is also helpful.
If you are thinking, "My o's are bad. My o's are bad," as you write, they will be bad.
Talk to your nib about where you want it to go.
With most curves, there is a sequence of more curve, a little straighter, then more curve.
Understand the ovals and talk to yourself about the path you are taking as you go around the curve.
Pay attention to the white shape that you are creating with the strokes.
Looking at the corner of the nib and guiding it along the white space can be really helpful.
Look at the right corner of the nib and you make the left stroke and the left corner of the nib as you make the right stroke.
Those two corners will define the white space.