Ooh, I like it! I wasn't even aware of those triangular tiles yet!
Yeah they are still pretty rare. You can get them from bricks and pieces, but in large quantity they are quite expensive. I got them from Legoland where you can buy 100g for 9€, which is okay especially for small tiles and stuff. Sadly you are limited on 100g per person and per piece so you cant get a lot of them.
As for the moc I think the shape turned out great. I am still thinking about what to build with it. A Dwarven city or fortress like Erebor, Moria or the ones from Warhammer would be interesting but also very big and part intesive. Only one column which i tested in LDD would be a thousand pieces