I've never been far enough above 35k to worry too much about it. I think I made it to 50k once, and over 45k a couple of times.
This year I wanted the 2 SSWUs so didn't choose the miles. I should hit about 35k this year. If I go over, I might credit it to BMI so I can use the Miles+cash redemptions. I'll worry about it more when I get there
Dr. PITUK