Well, it's not a 210, but I flew a Cessna Ag Husky for a while one season a few years ago. Turboed and injected 300hp Continental. It was a BEAR to restart when hot. The proceedure that worked best for me was to hit the boost pump for about 15 seconds with the mixture full rich to get the pressure up. Then, I'd start cranking with the throttle cracked and mixture back at idle cutoff, and start advancing it up to full rich while cranking. The engine would usually light off when the mixture got between about half to 3/4 of the way up. When she fired off I'd just advance the throttle and keep it running until she smoothed out. Worked just about every time as long as the battery was good and hot. I would think that the same or similar proceedure would work on the 210.