Exercise 3 - Experiment with mixed media

Sorry I've been a bit waylaid by life in general and Christmas card design in particular so it's taken a while to get to this exercise.
After some consideration I decided that I had dismissed too quickly the layout with toys from a previous exercise.

I've got some biggish sheets of cardboard from son number 2 who has been on a buying spree in preparation for working abroad for 6 months so that seemed the perfect base to work on

This is marker pen, pastel (both chalky and oil) and compressed charcoal. Does it need a background?

Going back to my earlier reflection I think I need to avoid drawing everything with a space around it so I used another smaller sheet of cardboard and glued some scrap paper onto it.

 I'm having trouble getting the paper to stick when I draw over it. Am I just being too impatient?
Again I've left space around my composition and not drawn right up to the edges. Maybe I can fix it with cropping?

A bit more punch. On the same lines I could improve my earlier attempts with cropping

Is this cheating? I do think it works better with the crop especially the bottom version.
I tried PVA to glue my paper down and found an old red matchpot of emulsion which I "drew" very rough shapes of the red areas on my board. Once it was dry I drew with pastel (oil and chalk) and compressed charcoal.

I'm always worried about overworking but this looks unfinished

Funny that I was sure that this more cropped image obviously needed a black background.
I do find it easier to work loosely if the support is cheap and nasty and if I corrupt it with stuck on paper but I'm still not sure what is the best glue to use. PVA did seem to work a bit better but the paper was rubbing off if I worked it to hard, I guess that is to be expected. I like working from a medium tone and adding lights and darks to create an image. Pastel is great for this and has the advantage that I can work over it although I haven't found anything that can work over oil pastel but oil pastel. Big pens like markers stop me from fiddling with detail too early as does working large. I avoided dip pens although I do enjoy using them because I find it hard to draw large with them.