And some notes about priority.
I don't know much details how current squeak scheduler arranging things,
i'm just want to point out, that you using relative priority in your
samples and in your proposed patch, by writing  Processor
activePriority +/- n.
This, in own turn uncovers another problem with current scheduler
implementation: it's not designed to use relative priorities in mind.
As people pointed out:
Processor highestPriority + 1
or:
Processor lowestPriority -1
makes no sense, and lead to errors or unpredicted behavior.
So, first, i think, that if you really want to use relative priority
values, you should make changes to current implementation do to it
well and without errors.

Now, let's say if you make thing in the way, as i proposed in post
before (use highest/lowest priorities to depend only from current set
of running processes), the only thing which is left is to introduce a
scale.
I proposing a logarithmic time slicing:
a process with priority N doing roughly twice as much operations as
process with priority N-1 for a given period of time.


-- 
Best regards,
Igor Stasenko AKA sig.