28mm Sandbag Redoubt - ready for a mould?

I've been working on this over the weekend, and think i've taken the sculpting as far as a i can. I'm pretty happy with the result, its a versatile piece, and could be used in many different ways. It'll be cast as a 4 piece kit, two sandbag U sections, and two firing step U sections, to make up a completed redoubt.

It measures 160mm by 80mm externally, and 120mm x 60mm internally, with the height at 32mm.The firing step is 10mm high. The pictures show it with 28mm figures; the models inside are on the firing step, and the ones in front at normal game table height.

I thought a single U section could also be used against a wall to make a smaller redoubt, and the firing step can be combined with my single biscuit boxes or sandbags, to make a small barricade.

I'll probably start making a mould at the end of the week, so you're welcome to post a comment for anything that needs to be changed.....