I left the skin on while curing, but once smoked, I'll remove it and then package it up separate to use in various dishes.
I'm afraid I'm of no help on how to control the saltiness. The guy who I got the recipe I'm using weighs the meat, then has a formula that you use for the cure.
As per his recommendation I weighed in grams.
Weigh your piece of pork belly.
Weigh the rest of the cure components:
Salt is 2.5% of the weight of the pork belly.
Sugar is 1% of the weight of the pork belly.
Pink Cure #1 is 0.25% of the weight of the pork belly.
Mix together the salt, sugar, and pink cure #1.
Here's the link to his video.
https://www.youtube.com/watch?v=LlvCFEgLZGc
If this new bigger batch comes out anywhere near as good as the first batch, I'll be very pleased.