So, back to my "problem", it looks like I'm safe to write:

      Dictionary new: runtimeVar

and, no matter what size, there will never be a performance hit over Dictionary new.  Whew!
 

The above is only true with what's currently in trunk.  With Collections-ul.867, there is still the case for

     Dictionary new

vs

     Dictionary new: 3

I hope I'm not missing something again, but because of that I think we should revert your change to HashedCollection class>>#sizeFor:, which is what this new Collections-cmm.870 with uuid c4bf7594-c44e-4d02-9956-2b727d2eb75b does (argh, forgot to up the version #, oh well).

 Best,
  Chris