Millisecond Forums

I currently have a study in which participants are directed from Qualtrics, to Inquisit, then back to Qualtrics. Everything is quite seamless, but I have a few issues that I need some help with before I send this out for participants to take part in:

1. Participants are intended to be randomly assigned to one of two conditions: 

<batch>
/ groups=(1 of 2)
/ file="stroop_deplete.iqx"
/ file="stroop manipulation instructions.iqx"
/ file="pasatc.iqx"
</batch>

<batch>
/ groups=(2 of 2)
/ file="stroop_nondeplete.iqx"
/ file="stroop manipulation instructions.iqx"
/ file="pasatc.iqx"
</batch>

It was recommended to select either Sequential or Random without Replacement for how groupid should be determined, and I have tried both ways (granted, not with a lot of participants) and I would like to know what might be best for what I am trying to do. I notice that most people who I have tried this out on have been assigned to group 1 (only 1/5 people were in group 2). I intend to collect data from ~215 participants, and I would like for the groups to be about even. It may be do to such a small sample, but can anyone tell me the difference between exactly what each option (Sequential or Random without Replacement) would do for my study?

2. Regarding the subject id--I have my survey broken into 2 parts (one Qualtrics survey for each), and I have my millisecond URL in the first Qualtrics survey set to send subject id. I have checked the data for all parts of my study, and while the first Qualtrics survey and the Inquisit data have matching subject/response id, the second Qualtrics survey has a different response (subject) id than the other two parts. Does anyone know how to make it so that the same ID carries through all 3 parts (Qualtrics-Inquisit-Qualtrics)?
 
3. Finally, I wonder if there may be a way to make the subject id numerical (and sequential) as opposed to a long alphanumeric string. This may result in a lot to sift through when all of my data is collected.

Any help is appreciated! Thanks!