I've got an idea about what I want to do, and where I want to put it in Dr Who canonicity, but can't decide which Doctor to use!
Well if the plot doesn't dictate the Doctor (mine narrows it down a bit) then I'd say go with whichever Doctor you feel most comfortable writing. Might not be your favourite, just the one whose skin you can easily get inside of.
I'm guessing you'd have less competition if you went for Hartnell rather than Tom Baker as well
