I noticed that my previous message in this thread has been partially addressed elsewhere. There, jcl pointed out that it is possible to have a demo account with IB without having a real account. I can confirm that. I tested whether zorro would connect to the demo account and it does (do not forget to install the IB gateway and to change the TWS API settings under edit/global configuration/API settings by changing the socket port to 4002 and enabling ActiveX and Socket clients - the error messages in zorro point to these two possible problems). Unfortunately, markets are closed and I can't be sure if actually z8 would be able to spit out the contract size for each of the assets as I get two errors: <asset> unavailable at this time and !Requested market data is not subscribed. We will see on monday. I am mainly concerned about the second warning as with just a demo account a data subscription is of course not possible.