I'm flying ORD-NRT and back on weekdays in mid-February. I'm now 1P and have more than 120,000 miles at hand, but I'll be 1K and get 6 SWUs in the end of this year (thanks to FT and double EQM!). What would be the best strategy to upgrade my flights from Coach to Business?

If I need to be more specific...

- If I upgrade (or waitlist) by miles now, will I be able to "exchange" the method to SWUs without any fee or penalty?

- If I try to insist that I have paper SWUs, how does it work? Do I need to know the code in advance? If so, what code would be the best to claim?

I searched but couldn't find optimal answers. Sorry if I missed something obvious...