Hmm this can vary greatly on the question type and so my response would be much toolong in order to nail down the numerous reasons why one couldn't identify an assumption. Do you have a specific PT question number I can use as a reference?
depends on if it's interesting .... if it's a lot of fluff then it's toolong. If you've only included things that are clearly relevant then it's fine. is it double spaced or single spaced? how many words in total? mine is a little over 1000 words.
@"Rigid Designator" I've been catching myself looking at my watch almost after every question, maybe sometimes after every couple if I felt I took toolong on a question
@"Giant Panda" I can't recall right now but someone posted their strategies on this not toolong ago. Try a search in the LR discussions. Hopefully someone will come along soon and can provide the link for you.