I also "brushed" my sections when I used my 1800 and disposable blades. I
also used my "Instrumedics" system. I never could get the guide plate to
work well with disposable blades and used steel blades, which worked. When I
ordered a new cryostat it was a Zeiss and it had magnetic blade holder
availability.  I called Leica and asked for the same for my 1800. Although
they had not actually begun to sale them in the states, they were very
helpful (and some what curious as to how I knew about the blade holder) and
I received one a short time later. It is the best alternative for a steel
blade.(actually a better idea for biohazard samples) I originally did a
price comparison on "regular" disposable vs the magnetic and found out that
the initial cost of the magnetic blades while more expensive to purchase was
compensated by the use time which was significantly longer. the blades can
be purchased from different vendors so shop around. The guide plate works
really well with these types of blades. anita