Nice effort Paul. This is time consuming and difficult processing so you've done very well I think, especially given less than ideal conditions cloud-wise.
Were you following the instructions on this page (adapted for newer version of Fitswork)?:
http://www.gva-hamburg.de/sofi2006/f...itswork_uk.htm
What settings for the radius/rotation angle of the filter did you end up using? Did you get an ugly black circle inside the corona and then just black out the whole moon?
Phil