If you held a gun to my head, I would say 200 is more shady than 100.
But it is VERY site specific. It depends on which side of the loop road you are on (east or west), very local vegitation, etc.
August is a HOT, sunny time so I would take a shady spot most-of-day before I would care about location (100-vs-200). It makes about 60 seconds difference in walking length (100-vs-200) but your AC can give you a chilled interior MUCH easier when you return IF you have a shady site.
Length of TT is no factor IMO.
That's my opininon - it's worth what you paid for it. I have never BEEN to WDW in June-July-August because I used to live in South Florida (back in the day) down around West Palm Beach) so I understand Central/South FL in Summer. You can manage it if you can take mid-day breaks from the parks (we boat to MK and drive to the rest) and avoid the hot/wet parts of the day.
Bama Ed