can you help me bid this job?

i am trying to bid a job for a family friend and want to be fair with the price. he would like to do a fake slate. but i know the pricing for that will be up there. i have done 3 round roofs before and was paid by the hour for shingling the round part of the job. this customer would like a firm price on the porch roof and another on the round roof. i would like to give him a price for asphalt and the composite slate. (what do they get for a square of just composite slate now? it was $360 a square last time i bought it)

thanks for any input.

here is a few pics of the job (the porch is just under 4 sq. it will get new plywood, ice and water the whole thing and flashing up the house. the round part is 10 foot at the botom and 14-16 tall)