A 2600 share will count for twice as much as a 1300 share, the only difference would be that it'd increase deviation, but should average out eventually.
That doesn't seem quite right. I just put in a 21,700 share, and it seems to be worth just as much as any other share I've put in.
The amount the share is worth is based on the target diff you were aiming for, not what diff the share ended up being.
So if you were targetting diff 1,000 shares, and you got 2 shares, at 1,074 and 7,771 then both of those shares would be worth a diff 1,000 share.
If you were targetting diff 2,000 shares, then the 1,074 wouldn't have counted as a share, you would have still got a share for the 7,771 one, which would be worth a diff 2,000 share, which should give you the same share of the payout.
(my example is probably over-simplified, but you get the idea)
-- Smoov