Given a sufficiently large number of participants, randomness itself will lead to roughly equal Ns across your groups. Inquisit does not provide any explicit means to control those.
Yes of course that makes sense. I am hoping to have at least 100 participants in the end - that will hopefully be enough for randomness.
Also, if you want subjects assigned to groups based on the groupid, you need to set groupassignment to 'groupnumber', not 'random'. See the documentation for the /groupassignment attribute for details.
I am not sure what you mean by this - or rather: I know and understand what you are saying, but am not sure why/how it is relevant to my problem.
This is what I am doing: I am using the site soscisurvey.de for my questionnaire. Participants will start out there by giving the alphanumeric participant code I provide them with. At some point in the questionnaire, they will be forwarded to Inquisit. The forwarding link has the participant code in it and I told Inquisit to get it from there, use it as subject ID and send participants back to the survey with attached subjID after IAT completion (this is all working perfectly).
From what I read above, assigning participants to groups based on the subject ID wouldn't work in my case because they are alphanumeric, right? And in my case, there is no group ID that participants are assigned by the questionnaire - that left me with "random" as solution. (the six different <exp> in my script are for counterbalancing block order to avoid practice effects. I really don't care which participant does which experiment, as long as its roughly balanced.)
Maybe I am missing the obvious here - I am quite the Inquisit newbie.