If you tried to 'mop it up' then about 1/4th of what was there was still in the 'mop' and I would say about 1/4th you just can't get off the ground... so I'd think you got back all you could. Or you could've been just running low on fluid
As for the pistons, replace them both, if you need any help PM me I can spot ya some cash till the Lil Switz trip in Aug.