All 027 on my layout (a little FT too). I used black floral gravel that I found at a local dollar store. Probably a little big but if I was that concerned about the scale then I wouldn't be using tubular track. 
At a buck for a one pound bag who's gonna complain.
The light gray and brown gravels are also a floral decorating product from Michael's. 
I thought about adding extra ties but I know this layout will get torn down eventually for a bigger one so it wasn't worth the time and effort. The next one will be GG and Ross switches.
Bob
