Ideal COAL is ~3.150 for the start of the BT to be just above the neck/shoulder junction. The bearing surface starts to go below the neck at ~2.900. Anything shorter than that would be silly. Somewhere between the two would be ok, but not ideal.
215’s in a WSM aren’t much of a benefit in a hunting gun over say the 185’s. Marginal case capacity to push them fast enough to get the advantages. Even less so if you are going to do a short barrel.