What was the original question?
I reread it and it looks like a few questions combined.
My thoughts on why things fly are looked at as totally wrong by a few of the number happy guys but IF the original question was "is span related to stall speed?"
the answer is -YES
Why?
Everything is related to the stall speed.
Size
Shape
Speed
In doing aerobatic designs - we found that you had to first determine IF you wanted a good fast abrupt stall --or simply an incredible fast braking mush that has no real pinpointed stall.
The single most important factors we found were these:
the aspect ratio
The fineness ratio.
The straight long wing - stalls ,breaks cleanly
The round disc (lowest practical aspect ratio)- simply moves the air outbound and the angle of attack can go to a impossible (or so it seems) angle- the stall simply does not show up.
The airfoils involved- really are not important -except they need to be stiff (will not twist under load).
the thinnest are the best -if the loading is low enough .
how thin?
our current stuff is 2.5%
To clarify --the chord is 10" the thickness is .250
I don't know how the numbers you guys use apply to all this.
If one is not involved in a hands on application of these super light overpowered model aerobats - then what I have just said probably makes no sense.
PS- I just realized that the original question may have been about avoiding stalls!
I am interested in setups which stalls on command -then is controllable whilst stalled - and the stall is easily and quickly reverted to non stalled flight.