Yes the pine is the best softwood to woork with. It is very friendly to the tools. The heart wood of the pine is very long lasting. But the weaker part of the pine is pine's sapwood. I have mentioned in some old buildings that the sapwood has rotten and the heartwood was still very hard and fresh.

I beleive it is very, very hard job to work with white oak. And hats off at your work. I have made some stairs for the exterior of the house from old dry oak - it was quite hard - but it was easier to make perfect shaped mortices with chisel if we compare to softwoods.

Hand work and hand tools give to the structures always much more value and historical evidence and story of the carpenter that has made it.

Goosewing gives perfect finishing to the timber. I also like it very much. I have discovered that this axe is like your college and teacher in one person.

I think that Gransfors Mortice Axe with a narrower bit would be the right one to use for the making of your grooves.

Good luck in your project

Jacob