a good way to make scuppers....

I've put on the rubbing strips - they're made of celery top pine - and I glued them down tucking in my fibrglass that I laid over the deck. The glass is now epoxied and ready to paint. Before painting the decks, I wanted to make and at least dry fit the toe rails, whilst deciding whether to epoxy the toe rails down prior to painting the deck or screwing and using a mastic-like compound.
So, I cut the toe rails with their tapered sides and went to cut the scupper holes. I tried with a router but that just shattered the wood. This was very sad because celery pine is expensive but lucky I only destroyed one of the short pieces of toerail. I could then use this piece to practice other ways of cutting the scuppers.
Next, I check Mike Randall's blog and tried his method - jigsaw then rasp. I couldn't do this either. Celery pine can be brittle and I was at risk of splitting off the bottoms of the timber.
So, after a bit of head scratching, here's the method I came up with that worked really well. I may not be the first one to do this but I did think of it myself.
After deciding the size of the scupper hole, choose a hole saw size that the scupper hole would be a portion of. Then, work out a spacer thickness that would occlude the part of the hole that you don't want and cut it from a scrap piece of timber. Clamp 2 toe rails together with the spacer in between.

toerail sandwich

then, cut the hole centering the drill bit in the spacer timber. Drill till the bit comes through then turn the sandwich over and cut from the other side (to avoid breakout/splintering)
Result - 2 neatly cut scupper holes from one cut!

two scuppers for the price of one!

here are some finished toerails

scuppers cut

and then I sanded them and dry-fitted them to the boat. Looks nice!

bow end

rear end