First, kudos to Umeå university for being forward-thinking enough to (gasp) allow you to own your own work.
To answer your question: If I were in your position, I'd try to work an option 1.5 -- see if you can take an unpaid leave of absence for 4 months and spend that time working on your startup. Most universities are happy to let their faculty do this sort of thing, since they usually come back far more excited about their research than when they left.
Spend those 4 months working on your startup full-time, and plan on deciding at the start of the 4th month whether you're going to take your option 1 or your option 2. I don't think you can really make a rational decision without working on this full-time for at least a few months.
Re your startup: Have you considered putting it together with freebase? I don't know how structured your input databases need to be; but since freebase is basically wikipedia (EDIT: and apparently other data sources now, too) parsed and converted into a database, being able to run natural language queries against it could be very interesting...
Actually it's a law in Sweden called the "teacher exception" ('lärarundantagen') and it is not without controversy. But it was the business development folks at Umeå who let me in on the secret and gave me a lot of encouragement.
Yes I am considered taking a leave next Spring. It would be difficult to Swing this Fall. And if I did take a leave, I would definitely move to a start-up hub. I really agree with Paul on the need for that.
As for freebase, yes I had considered that earlier and indeed I should check back. Alas a nice thing about having my system as an open-source system, would be that I could get a masters student to do the integration with freebase as part of a project...
To answer your question: If I were in your position, I'd try to work an option 1.5 -- see if you can take an unpaid leave of absence for 4 months and spend that time working on your startup. Most universities are happy to let their faculty do this sort of thing, since they usually come back far more excited about their research than when they left.
Spend those 4 months working on your startup full-time, and plan on deciding at the start of the 4th month whether you're going to take your option 1 or your option 2. I don't think you can really make a rational decision without working on this full-time for at least a few months.
Re your startup: Have you considered putting it together with freebase? I don't know how structured your input databases need to be; but since freebase is basically wikipedia (EDIT: and apparently other data sources now, too) parsed and converted into a database, being able to run natural language queries against it could be very interesting...