There is already an international valuation benchmarking tool called ‘D-Risk It’ that you may find helpful. I am the founder of DRI and I developed it out of the frustrations in talking to startups when selecting them for the angel investment network that I used to run. It’s a free valuation test and we are now seeing adoption by accelerators, crowdfunders and angel networks.
It can give pre-money valuations, from concept/seed stage all the way up to VC seed stage, no matter where in the world you are.
Further more, the valuation is just one small part of the D-Risk It startup ‘Deal Report’ that highlights a startups level of investment readiness.
There is an online version being trialed by the above groups (accelerators, crowdfunders and angel network) but you can see the same valuation tool and deal report in the app: www.drisk.it