For the Index token I was working together with 
In my opinion it's easier to this with several specialized accounts. However this would have been a nightmare to code. We needed to come up with a solution with a one account curation strategy.
The challenge: one account and different hive-engine tokens to curate
To be able to code everything in a smooth way, we decided to keep all the stakes on one single account. To provide as much dividends as possible for the token holders, it is necessary to use these stakes to curate posts. This is quite challenging because you can only vote 10 times 100% per day. If we vote 10 times on Leo posts, then there won't be any voting power for all the other tokens like stem, archon, ctp, pal, sports and now neoxian that are in the index.
The solution: the vote weight multiplier
Scotbot that is linked to the hive-engine tribes and that makes them actually work the way they should, includes a function where you can set a vote weight multiplicator for a tribe token.
The vote weight multiplicator explained
You can set for every token a certain vote weight multiplicator individually. Let's say we put this multiplicator to 2 for the LEO token. This means that my Hive vote will be multiplied by 2 in LEO. If I vote a post on Hive with 50%, this will give a 100% upvote with LEO.
How we set this up
First I have created curation trails for the tokens that are supported. I made one for LEO, SPORTS, PAL, STEM, CTP. Since Archon and Neoxian are kind of generic tokens, there wasn't the need to create specific curation trails. I made sure that these accounts were voting around 10 times per day on posts with a minimal quality standard and that carry the appropriate tag. For these curation trails, I've set up a list with around 30 to 40 authors for each token that are repeatedly posting quality stuff in these tribes. The 10 votes a day are attributed randomly among these authors.
We have now several curation trails that vote each 10 times a day on the different tribe tokens.
For the main account that has all the tokens staked, we follow these curation trails with 20%. Meaning that each vote of the curation trail will trigger a 20% vote of the main account.
The next step is to set the vote weight multiplier to 5. Each 20% vote in Hive becomes a 100% vote in the tribe token.
By doing that we managed to upvote 5 hive-engine tokens with full voting power and one single account. At the same time we manage to keep the Hive voting power stable.
One big problem: multi tags
The only big problem with this approach is that when the curation trail votes on a LEO post, there is a chance that this same post also has a #palnet and a #ctp tag. This means that there will be a full vote in LEO, in PAL and in CTP. Therefore the voting power will go down for all 3 tokens and it's quite difficult to guess how these tags will be combined.
The solution: fine tuning the vote weight multiplicator
The easiest way to correct this is to check regularly the voting power in the different currencies. We have created a tool to do that. Leofinance also allows you to check the voting power and the vote weight multiplier. However you can only check accounts that you own the keys for. If the voting power is getting lower in a certain token, we will decrease the vote weight multiplicator and try to fine tune this to keep the voting power in all tokens between 80 and 99%.
This fine tuning can be done once a week for example. It's the only manual component of the Index token project. All the rest is fully automated so far (This might change once we build a town in dcity)
Learn more about the Index token
This concept can be applied for any account size
If you have only one account and you would like to curate in several tribe tokens, you can easily replicate this model. Be aware that curation returns are often much higher in tribe tokens than in hive itself. Especially for small accounts, this can be a very interesting approach without the need of creating different accounts for each token.