BTW, the 090 uses the same bar as the 050, 051, 075, 076, 084, 088, etc. Only difference is the tensioner hole and possibly the oil hole will need to be redrilled and positioned further out on the bar. Drive link count for any given bar length is the same.
z4 will probably have a good deal for you, so I'd go with him first.
Got a friggin' 48" bar/chain I'll probably never use.
Chris B.