Just finished my full frontal button up one.
cost £15 from ebay.
Dyed in black (£5) , took off all the buttons and pull cords before I dyed it. Sewed on large black buttons(£2) and replaced the pull cords with black parra cord(£3). just waiting for some pull toggles(£2) for the cords and I wil be set. Total outlay of £27, not bad.
Waterproofing I will use fabsil, I know someone else who has one and they used fabsil and it works fantastic. I will be using it on my dutch polycotton smock as well.
Mine was enormous, even after a boil wash, even too big with all under layers on etc, so I took it in by about 6 inches at the back and it fits perfect. Probably went from an xxxxL to an XL which being a 38/40" chest is spot on with underlayers.
Taking it in was much easier than I thought, just followed the rear crease and pinned it where I wanted it, tried it on a few times adjusting to fit, then did a running stich up the back, misssing out the pull cord bit, then sewed the flap of material over at the bottom so it lays flat against my back.
I dont know how to post pictures on here, once I know how Ill post some.