What a thrill to see a new carving so well done in progress. Makes me smile to admire it.
Give a second thought to carving dry birch. That will go from cheese to bone as it dries.
However, the tradional birch burls for kuksa are bullet-proof-tough wood.
True, a Mora #162, #163 and #164 are meant for carving the void insides of bowls and kuksa.
I don't think that the steel in the Mora is worth the money.
They are a bitch to keep carving sharp because people tend to pry out chips and bust the bevels.
Have you got a local farrier? Go see them and ask about their used/worn down crooked hoof trimming knives.
I pay $5.00 each, about 3BPS, to pick through the box of dead knives. Maybe buy 5-6 at a time.
There's a lifetime of good carving steel in them, just need to be tuned up.
http://www.hallknifeandforge.com/
Tell you what, Sundowner. PM your snail mail address and I'll send you a Canadian Hall farrier's knife, very well worn down.
I cut the bevels from 25* down to 12* and it will be "carving sharp". You learn to keep it that way.