Adjust B&W paper development time when using Uniroller?

Hi,

For the first time this evening I developed a B&W print in my
Uniroller drum on a motorized Uniroller base. I am using Ilford
Multigrade IV RC "Deluxe" with Ilford Multigrade developer. Having
never used a Uniroller before (and being unable to find directions for
B&W print processing with it on the web), I just followed the paper's
instructions for dish developing, using a dilution of 1:9 for one
minute.

This first print was a series of test exposures starting with 2
seconds at f/11. Now I realize that agitation and development time do
not affect paper in the same way as they do film, and that saying 2
seconds at f/11 is completely relative to the density of the negative.
Nonetheless, I was rather shocked to find that the the print came out
absolutely completely black -- absolutely nothing came through, not
even a hint of that 2 second exposure. So I experimented with the
development time for the uniroller, and found that if I developed for
only 20 seconds with constant drum agitation, I got relatively more of
normal image (normal given that I was still over exposing the print by
two stops -- see below).

Now this is all very disorienting to me (I feel as dizzy as I myself
were spinning in that drum!). I mean, it seems like I eventually got
an ok print when developing it for 20 seconds (the final exposure time
for this particular print turned out to be two stops less than where I
started, half the time, and down from f/11 to f/16). But I'm working
with a questionable negative, and am unsure if what I don't like about
the final print is the negative, or whether something about the print
process is mudying the print. Given my set up, I don't have a way of
developing in trays and comparing the results with what I'm getting
from the Uniroller.

I AM SO CONFUSED!!!

Is there a rule of thumb for print development time with a Uniroller?

Should I try working with the multigrad developer in a more diluted
form (ilford suggests 1:14 as an alternative to 1:9)?

And does anywone know where I can find information about using a
Uniroller for B&W processing on the web?

Thanks!

--Phil