Picked up a couple of these. Loads of folding and nice big parts. Look pretty straight forward. Requires coupling hooks, wheels etc. very nice toto
I haven't had a go at any of these but I have seen a built of one done on the old Guild forum and it looked (like the rest of the range) to be a pretty good kit. One thing I do recall is that the gent who built it, added and extra layer between the inner and outer sides to give them a more prototypical thickness to the planks.
Although the gent on the Guild used a rectangle of sheet brass in reality you could if necessary get away with soldering a rim from scrap etch with a cross piece to support the middle. That said I recall that you picked up some brass sheet so perhaps you won't need to mess about with scraps.