I’ve never felt that the ballast we use accurately reflects the prototype and I don’t think it’s the size. On that matter incidentally Stephen Williams in the seminal series, Great Western Branch Line Modelling, says that the top ballast was no more than 1 and a half inches in diameter. (How we pine for those pre-decimalisation days!) The problem to my mind is the way we secure the ballast. Using a water/PVA mix (or better still, so I understand, water/Copydex) the granules coalesce when wet creating to my mind a surface smoother than it should be. I’m sure others can describe the effect better than me. Ballast is rough and uneven but you lose that effect when you wet the fine granular ballast we use. Given that there’s no other feasible option to fix it I think I’m going to use a coarser ballast when, or rather if, the trackwork for Blagdon Mark II ever gets completed. That’s another long story!