This is not a problem, Zoly. You can scrape the rabbet using a sheetrock cutter's blade. Use the glue line\border as the guide and carefully scrape until you have a groove. Continue scraping until you satisfy.Hello guys ,I messed up a little bit,I glued together some keep parts before I should cut the rabbet first instead
Also, suggesting to glue all keel\stem parts together using the template. This will give you the exact match and precision assembly.