Heat will evap the alco and the with kief alot less would be needed.
I would say 1/2 oz per fith of lower quality bud.
High quality kief would be more like 5-6g's per fith.

Just to make sure we are talking about the same kief.
Compressed kief= hash.

Unless I had a but load of kief I would just smoke it instead of putting into tincture.

Typically this method is for lower quality bud.
They idea is to extract the thc only.