Unusual, an average of 100 protocanes per last year's canes.

Wouldn't mind seeing a picture.

There's no room for that many canes to become a productive size when clustered around the original cane. My guess they will be stunted unless you thin them. Compare their growth with other neighborhood raspberries.

I would think 6 new canes per old cane are plenty, especially for year 2 of the planting.