just to throw more sand in your eye...

I have put my sekonic 358 w/ incident bulb on the easel a couple of times... nothing worth feeling confident about.. but I THINK (stress THINK) that it should work. All you really care about is total vol. of light after all...

so -

after you have made one sucessful print at size X -
pull the neg. from the carrier but dont change the head height -
set your incident/spot meter on the easel -
take a reading, and adjust the ISO untill the time matches your exposure time for the last sucessful print -
raise lower the head as desired -
take another reading -

I'd guess it will give you the right exposure for the print.
dial in your time, put the neg back in the carrier-
and expose the paper-
if it comes out totaly screwed up -
say my name in vain along with a good many explicative/descriptive terms