Getting the engine heated up as quickly as possible is important. When starting the engine cold, get it running so it will run without the glow driver by driving it around. I usually throttle it a bit and run a few straights. If it cuts out at all while warming up, it's too lean and needs to be richened up a bit. If it's winding up slowly and real smokey, lean it down a little bit and do a few more straights wide open throttle. If it's too rich, it won't warm up enough to get to normal operating temp. I always start rich and work leaner running WOT passes in between adjustments to determine if it needs more adjustment. I will lean it down until stops stuttering rich on the top end. If it revs up and keeps revving up cleanly with no stuttering, then the high speed needle is set to peak. Once at peak, it's always a good idea to back it off rich about 1/16th turn. Set the idle needle so it can idle for about 15-20 seconds and throttle up cleanly. If after that 15-20 seconds it quits when you punch the throttle, it's still too rich.

When it comes to break-in, I'm not a believer of idling the engine for any amount of time. They don't get hot enough which causes more problems and doesn't really allow the parts to bed in properly. The parts that are the most important to seat during break-in is the connecting rod bushings. These bushings seat when run at rpm under normal loads. The piston/liner take care of themselves during break-in as long as the engine is run at operating temp. Fire it up, run it rich for a little while driving the truck, then lean it down to peak and back off rich 1/8 turn so when run WOT it stutters a little at the top of the rpm range. Lean the idle needle down so it idles nice and revs up cleanly. If it starts to get too warm, run a WOT pass (which should be more rich than normal running) which should cool it off.

Nothing magical about it. Fire it up, get it warm, and run the dickens out of it. No need to baby it or run it way rich. As long as the engine is warm, you're safe. Don't get caught up with tuning the engine to run at any specific temperature - if you do you'll just be wasting power (fuel) and possibly causing extra stress on the engine. I rarely check the temp of my engines - if they are running right, they're at the right temp. Checking the temp for reference isn't a bad idea for novices, but use that for reference only. Just my $.02