So yesterday after Dave's reply and some new insight I was confident I could apply my subjects' preference.
Now, I can run the experiment but after the surveypage (containing the question of whether 6 or a correspond with yes or no) Inquisit quits functioning and tells me that the branches contains - I quote - wrong element types.
The branches are as follows:
/branch = [if (radiobuttons.preference.response = 1) expt.version6]
/branch = [if (radiobuttons.preference.response = 2) expt.versiona]
The expt. elements are as follows:
/blocks = [1-2=sequence(practice, target)]
/blocks = [1-2=sequence(practicea, targeta)]
In my humble estimation, that should fit perfectly. Yet it doesn't. The error 'wrong element type' makes me suspect expt elements are not applicable in branches. Yet, considering Dave's comment, I doubt that.
Another question on this topic is the following: since the choice of an experiment depends on the subjects' preference, I decided to make a third experiment just for the surveypage. Since if I build the surveypage into either/both expt version6 and versiona, participants are already in an experiment where the yes and no key have been determinated. Therefore, when I press ctrl +F5, I want Inquisit to run the expt.survey element before choosing between expt.version6 and expt.versiona. The problem here is that I don't know how to adress this order of expt. elements in Inquisit. As far as I know, there is no 'higher' level in which you can arrange the expt elements (like you can arrange block elements via the blocks attribute in the expt element).
So these are my two further questions:
1) What can possibly be wrong with the branching?
2) How can I get Inquisit to start with the expt.survey element?