I made some sashes recently from accoya but i used polyurethane and it worked fine. In the spec sheets for accoya I'm pretty sure it says to use polyurethane.
Have you considered "multi construction" drill bits. I use the Bosch ones quite a lot its handy not having to change from a wood drill to masonry drill all the time. The few times ive used them on metal they've been decent too.
You could buy round magnets, sink them into the wood with a large forstner bit and glue them in. Im pretty sure I've seen magnets with countersunk holes in too which you could just screw on.