Thanks to a trip to the states which included unexpected upgrades on UA (huzzah for their massively overbooked flights - they bumped well over a dozen people on an ORD-LHR flight) and the resultant 2x and 3x miles, I'm within striking distance of 105,000 miles, which IIRC will get me a business class ticket to Tokyo. I've been wanting to go there for a decade and if I actually finish this PhD I might as well reward myself. I've never cashed in before and had a few questions which I hope you guys can answer.

- obviously, with bmi not flying to Tokyo, I'll be using another carrier. I just checked Expedia and noticed that both LH and SAS do one-stops (I'll be coming from EDI or possibly GLA); would bmi give me a choice of carriers, or is it a case of whoever has seats available? Are their business class amenities roughly equivalent? - if I'm splurging I want to enjoy myself as much as possible.

- how far in advance should I book? I know sometimes the free seats go verrrry quickly.

- if I want to include a brief stopover in Ho Chi Minh City, is this possible? Would I need to cash in extra miles? Or would it be easier to book the Tokyo flight and hop from there to HCMC and back again on a separate ticket?

- anything else I should know about or consider?

Thanks!

Also, thanks to anyone who responded to my 'will bmi renew my silver if I'm 54 miles short' query a few months back - they will and they did.