Yes I agree....it is going to be very very heavy.....are you sure you want a demin backing ????????
you are going to have to use a large needle, maybe even a 100 or 120, and really take your time quilting as
your machine will be going thru two layers of demin and I am assuming batting....you will really need to
use a walking foot for sure......
If it was me, I would use a blue print cotton backing, maybe like a plaid rather than demin....just a suggestion.