Col
Do yourself a favour and remember to rout-out a drip groove on the underside around the sink opening - it stops drips from hanging on the underside of the top. I treat the underside and visibe edges around sink openings with a PU wood hardener (Bondaplas-Voss) after sanding (waterproofs them) before giving everything 3 to 4 coats of oil (normally boiled linseed with the customer being told NOT to use the worktop as a chopping board - some BLO contains driers which taint foodstuffs).
One tip - if you are doing this for a customer, or even the missus - it's a nice touch to turn the sink cut-out into an extra large chopping board (square off, round over the edges and corners then rout-out two finger grooves in the ends). I always present this when the job is done.
Scrit