Well, I guess I need to give more details!:

How did you pick these?
No special way, except that they are a few options I've seen for the price range I had im mind, and I was thinking about using a hi-start instead of having a motor on it to keep it more simple, but that hasn't been 100% ruled out yet.

How will you launch? - Toss it off a cliff into slope lift?
Our flying field is on a hillside facing west, so most of the year we get good conditions for thermals.

What is your landing area like? How big? Rocks? Soft Grass?
Our fild had nice smooth grass runways - no rocks.

What transmitter will you be using? ( goes to mixing and such )
I have a JR 9303, so any mixing I need to do is possible.

I presume you are thinking thermal soaring as opposed to slope soaring, but you do not say. Different criteria.
We actually at different time of the year can have both conditions at our field, but mostly thermaling, since that's what we get most of the year.

Both are about 100 inches. Anything magic about that number? Why not 2 meter, 3 meter, 4 meter?
No, just a good size to see that are resonably priced and easy to transport. I'm not really opposed to any size, just want to keep it easy to see, so I thought around 100" would be a good starting point.