it is up to you if you want batting- i always use batting- but i like them nice and heavy/warm- some people just use a front and back- some people use a layer of muslin- some a very thin (low loft) batting- and some (like me) warm & natural---
it is a personal choice-
maybe start with something small- make a 12" block out of denim/homespuns- stick a piece of batting in it- quilt a cross on it- stitch 1/2" around the outside- clip it- wash and dry it- see how you like it- if you think it's too much- well then you know- if you like it ...continue on- the block can be added to a pillow or something to go with the quilt later. or try 4 (practice) blocks with different layers/ no middle/ muslin middle/batting middle/ flannel middle- and make a sampler to refer to later- each will fray differently- and have a different feel- and you will have it to compare to and see what you want to do for different projects.