Just had 1" hose available so was thinking of possibly using that.
According to my fluid mechanics book, Head loss due to sudden contraction H = K*V^2/2g
K = (1-d^2/D^2). d = small diameter, D = bigger diameter. And K from all the other fittings is ~7.4, so it was only an additional 0.75
So i thought it wouldnt be TOOOO much velocity loss. But its been 3 years since ive done that subject and i am most probably oversimplifying things, probably forgetting how it will the type of flow in the smaller pipe will affect fluid friction and the major losses. Now i am rambling.
Oh well better get some 2" hose, better safe then sorry.