Your email address must have been entered wrong. The owner of Sjmot@aol.com says she owns green tractors not red ones!
The answer to your question is that the magnet is just a slide fit. Use a screwdriver under one end and gently pry it straight up.
Rice Equipment at 814-226-9200 sells a brochure that gives some info on theory and repair of IHC magnetos. Worth the expense, but it is not a full fledged manual.