...good, outside the box thinking Batman, they would work well, small flat lead weights can also be useful !
PVA poured in a dish and left while to evaporate and thicken should work a treat depending on how thick/absorbant your card is,
its too 'wet'? straight out of the bottle.
50 years ago (pre cyno) it was the only glue available in the commercial art world for assembling mock up card packaging etc,
then along came Spraymount and changed the game ! would like a £ for every can of that I've inhailed over the years !!
I'll be joining you on the card modeling front before long, the way things are going -
had no idea of the wide range of model subjects available in card kits, stunning projects to build.