Throwing lance is 1 slot, axes are 2slot, so how about 35 cut when used as 2hander, and 2 slots. The high weight is good, keep ppl from carrying 2 too often, or maybe Unsheatheable (who carries a sheath for a double headed axe?)
TBH tho, since Dead Island was released I have been in favour of ALL melee weapons being throwable. Not accurate or ranged, EG: with no throwing wpf or PT, throwing your greatsword at a kiting archer is probably gonna fail cause it falls 2 metres away, but it would be nice, especially if you have a 1handed sword, archer runs off, fling it at him: if it hits him, hes hurt, but you have no sword, so it wouldnt be OP.