REMO - UK to Canada questions

My ex husband lives in Alberta, Canada, and has done since we split eight years ago. Because he has been extremely difficult, it has taken me until now to initiate both a clean break order with regards to his pension and also to discover how much he earns. It turns out that he is making around £150,000 a year and the amount he is paying isn't even the CMS recommended amount. I have discovered that I have to apply for a REMO and that they will then apply for maintenance, but I am confused about the calculations used. Are they based on the UK amounts, or on the maintenance amounts that would apply in Alberta, where he lives? (There is a huge difference in the amount he would have to pay.)

Does anyone have any idea how long it will take? The REMO email said that they were three months delayed in dealing with paperwork. Any tips at all would be very gratefully received.

Thank you in advance!