Ace video OP, where have you been hiding?! Great build, well thought out tutorial- I'll have to find your YouTube channel. I'll be building one of those as soon as I get the chance!
One thought- instead of PVA and sand, which I hate doing because it's messy as hell and takes forever, you can make a texture paste with PVA, sand, water, paint and I add in some filler powder too. Gives a great result and far less hassle.