Mashing; In a Tun or in a Pot?

I've tried two methods;
first method (and worked great); Preheated water into Tun (cooler) added grain and adjusted to 152F for 60 minutes.  Sparged and collected wort over a 90 minute period.. Excellent beer!
second method (stuck sparge); Protein rest at 122 in pot for 20 minutes, heated to 158F and poured into Tun (cooler). Sparged (stuck, and a disaster) sparged and  collected wort over a 2 hour period.. Excellent beer!
third method (and worked great); Protein rest at 122 in pot for 20 minutes, heated to 152 and maintained in pot for 1 hour, scooped out (too heavy to pour) into tun and sparged and collected wort over a 90 minute period .. Excellent beer.
fourth method (and worked great): Protein rest at 122 in pot for 20 min, heated to 158F and scooped out to tun and let set for 1 hr then sparged and collected wort over a 90 minute peroid.. still fermenting.

Local beer supplier is telling me to use the Tun for Mashing (1 hour) but I can really maintain the heat control on my burner.  I lost about 4 degrees in my Tun over the 1 hour perio on the fourth method.

What do you all think?  To me the Third method was the easiest.