Since Bic Cristal pens are my writing tool of choice, I have to say I find it strange you only mention Bic. Maybe a Bic pen isn't the right tool for how you write, but you can definitely use it without getting cramps.
"We must find ways of holding modern pens that will enable us to write without pain. …We also need to encourage efficient letters suited to modern pens."
Can you describe the way you hold your pen when writing and perhaps comment on the way you form your letters? I'm interested as I find the ubiquitous Bic impossible for more than a couple of sides.
