Hi, I did one from yew and I used a goose neck scraper and sandpaper to hollow it out. It wasn´t very extreme HLD but still it took its time. It was slow to work only with a scraper but that helped me not mess it up, but still very doable with soft yew wood. I used my fingers for calipers. Maybe you want a spoon or hook shaped chisel if you´re doing harder wood than yew. Good luck