I will be interested to see how this progresses. I have been doing my own in a different way. I have constructed 5 portfolios (so far) based on coins in the top 200. The first one has coins starting from 6 downwards plus one rising star. The others have rising stars - i.e., coins that are ranked in top 200 now which were not ranked in top 200 in November. I have weighted each portfolio equally and have not decided yet what the rebalancing strategy will be. I have not pinned down against what to index the portfolios. At the moment it is just against BTC or ETH price. I may use the Coinist indexes.
I am not sure if you are doing this but my portfolios are actual portfolios trading on exchanges across the world.
If you'd like to send me details on the diversification you're using (namely which coins/tokens), I can add your strategies into the competition/google sheet. I'm definitely interested in testing out what other people are doing.
RE: benchmarking - at the moment my main benchmark is USD with secondary benchmarks of BTC, ETH, DASH, BCH, XRP (don't really have a specific reasoning for those last three), and the Market Cap as a whole.
Coinist indexes could be an interesting one as well though it seems to lean more towards benchmarking the ICO market which might not be a completely fair metric to measure against.
I have written a lot about my portfolios. Http://mymark.mx/BehindTIB5 was the first. Search helps to find the next 4. Portfolios are all here http://mymark.mx/AltCoin - I will add the links in each sheet page.
Real money on each page