Why don,t you make the superstructure out of card first, its easier to work with cheap,and if you make a pigs a**e of it,at least you,ve not wasted a load of plasti-card,then you can try again until you,ve got it looking good,and all you,ve got to remember is,as long as you,re happy with it, thats all that counts,
As for Aldi slug traps,I suspect there only good for the job they were made for,catching slugs and possibly other creeps!
Wullie