If you are really concerned about warpage I would make a treating fixture. But to be honest if you take your time with a rose bud torch and heat everything slowly you can get as good of results as an oven. Drawing it back after quenching is actually more important than the heat treating process...
Stumbled across the site looking up information on scrapers. I am a licenseed tool maker and worked in a tool shop for 12 years. Moved to robotics about 9 years ago. A few months ago I was in the market for a snow mobile when I came across an emco maximat with a milling head that was brand new...