Best practice for bunker building

[chortle]

I've many of the excellent Pendraken WW2 bunkers, trench systems, and other buildings with roofs to put together and paint. I'm wondering what the best practice is for accomplishing this.

Resin is a lovely material, and a boon to the wargamer. The down side is that it does warp. The "lids" of the bunkers are not quite flat. Do you Fill the underside to make it even, or sand away to make a flat lid (one that fits squarely on the bunker)?

I will want to have the top of the bunker secured onto the model when I don't need it open (to put troops in). So I am thinking of drilling each corner of the base, inserting pegs into the holes, inking the other end of the pegs to see where they lie on the model, and then drilling matching holes in the model so that pegs hold the roof in place when you want it there (detachable). Does anyone else do that, or perhaps have another system?

[Genom]

I make most of my buildings and bunkers out of foamcard and I tend to glue bits of matchsticks to the underside so that it slots into the top nice and snug.

[barbarian]

What about nice magnets ?

[nikharwood]

I filed the underside to get them flush...I like your idea of some pegs to secure them in place.

[chortle]

What about nice magnets ?

Lovely, lovely idea. I happen to have an excess of magnets too tiny for most uses.