Many years ago I self-learned English Roundhand from "Copperplate Calligraphy" by Dick Jackson and "The Universal Penman" by George Bickham. As a slope of 55 degrees is used throughout both of these bools, I assumed that after experimentation this was decided as the ideal angle to produce the most beautiful form of this lettering. I think that it's worth noting that the writing master George Shelley wrote Roundhand in 1709 at an angle of 62 degrees, It's significant that this was never adopted as the normal slope and by the time of The Universal Penman, 34 years later, a writing slope of 55 degrees had become the normal, acceptable practice.. Of all scripts English Roundhand is my favourite and, as a traditionalist, I have never seen any point in deviating from this ideal. Of course, there are no Copperplate police out there, and any deviation is entirely up to the individual. Having said that, I have still to see any English Roundhand which benefits significantly from being written at a different angle. I know that there are attractive versions of this style, but in my opinion if the writing angle is too different, it should be labelled as a variation to avoid confusion.