Ben-B, After skinning 3 kayaks with canvas here is what I've learned. Mildew is caused by storing a kayak in a place that is too damp, which is basically everywhere out of doors. The first coat should be of Thompson's waterseal or something similar. Then after it dries apply whatever you want over top of it. My favorite coating for canvas is 50/50 boiled linseed oil and a flat oil based exterior paint for the first coat, let this dry for 5-7 days in a warm place and then use 30% linseed oil and 70% paint and let this dry for 5 days or so and lightly sand this second coat for the third coat 25% linseed oil and 75% paint let dry for 5 days and lightly sand , install keel rub strips and your done.

Oil based paint mixed with linseed oil remains flexible and will not crack over time.

The important thing is to store the boat in a dry place, indoors if possible, and if not then dry it out in the sun before putting it away.

The water beckons...