As far as I know, there is no generic standard for venting of 90+ furnaces. There are limitations on where intakes and vents terminate which are prescribed by code, and are standard. The actual sizing of vents and the equivalent losses for fittings varies by the manufacturer. When dealing with venting of these appliances, nearly all codes digress to 'installed per manufacturers specifications'.
Hope the customer has the literature/installation manual for the furnace.
That being said, I do know that you will not find an equivalent for a short sweep 90. I've yet to see or hear of a manufacturer allowing them.