I'll echo the comments above from Thexder, Seabolt, Epoletov & Walrus (and others).
An hour or so is about the maximum that I can afford to spend per turn on any one battle. With that I can handle doing a turn per day. Anything more that that and my focus and enjoyment start to go downhill quickly.
Over the past couple of months I actually found myself involved in too many battles at the same time. Not only my turn rate suffered, but I was not able to focus 100% on any of the battles and the quality of my game suffered (and my apologies to my opponents during that time).
So a 200x200 map for 60 turns would take a very dedicated SP player - moreso than myself.
Deadeye