Hi, I'm no expert.. but, I've done a bit of reading here.. some from folks that use Coopers. That was my first brew.. which I haven't tasted yet.. still carbing.
I think.. ummm... Using two kits may over hop your brew. Some of what I've read is to use one kit and one tin of plain malt extract.. probably the Coopers Light ME. As I understand it, there will be some unfermentables.. still haven't figured that out.. but, I think that might get you someplace.
One suggestion is to go to the Coopers website. They have Coopers Talk. There is a forum that has some recipes.. many are straight kits.. others are modified kits using the suggestion above. Worth a look.