Freelance Admin: How would you charge? Posting for traffic

[LMW1990]

I am a freelance medical transcriber in my spare time.

I usually charge a flat fee per audio minute. It's straightforward and works for me and my clients.

I have been approached by a client to create letters based on the consultants hand written notes and the standard forms they fill in (so some printed material). Each pack is approx 7 pages of info, not everything is completely relevant.

Obviously the patient details and procedures/ diagnosis are unique, but there are some paragraphs which (after looking over a few packs) will be standard such as procedure risks.

I'm unsure how to charge for this work. Per hour? Per line? Per word? Include the standard paragraph if per line/word?

I think I'm over thinking but I am trying to strike a balance between not taking the mick with a newish client and not underselling my service!

Any words of wisdom?

I would charge per hour for the first load, add on a 20% contingency and use that to calculate a base rate for each letter/ pack. That way you earn more as you get more skilled at it, but your client is also getting a fair deal.