Cutting the deck off
Cutting the deck off is no easy task. You need a grinder with a fine cutting blade and a steady hand and you need to make sure that you cut higher than you think you need as the flange is very close to the top. If the hull is still original and hasn't been resprayed you should be able to see the glue line. You need to cut above this line. The first hull I cut I didn't cut high enough as the picture left shows.
I cut about 220mm from the bow and back about 1000mm. You could probably get away with not cutting so much of the deck off but this will restrict how much spread you get back towards to bridle fitting.
I cut a lot higher on the second hull and got it close so most of the flange remains. I am keeping the deck pieces as I want to re-glue it back on later.