It depends of the temperature all around. Sometime it will become sticky on the surface and it will be difficult to remove. Personaly I put a good coat of linseed oil, I let it 10 minutes and then I remove the excess. The oil will become hard into the micarta between 1 night and 2 or 3 days.

If you polish your canvas micarta with Superfine Woolsteel ("0000") it will help to have a regular color.

Boiled linseed oil is darker and will become harder (so it seals better).