Hi Robert,
I've been attempting to contact you. I too operate a katchu restoration studio, located in Northamptonshire. I'm mainly self self taught through years of experimentation, trial and error. I outsource any metal work and keep mainly to either lacquer work and lacing. I must admit that Ian and Jock got me started on this journey when they were restoring items in the past.
I have been professionally trained in urushi application. Unlike you, I lean towards commercial restoration as my clients are on limited budgets, where traditional restoration is completely unviable. Keeping it authentic is costly. My view is that any material used is modern, I source printed leather, kanamono and silk odoshi from Japan, but try to use vintage asa, chirimen silk etc.
I do own a personal collection of some 30 gusoku, Kabuto which makes for an excellent resource of study should you ever wish to view them.
Hope we can meet.
Dave