In the last week or so I read an article with advice for Sprints especially but applicable across the board. To paraphrase: Pick a route and MAKE it the best route choice by running as hard as you can - and thinking as clearly as you can. Changing and "deciding" are such time wasters. I expect it would be very much the same with MTBO.
No in MTBO there are very much 'better' routes to pick but once you've picked one, no point going back. With sprints you should definitely stick with your first choice and just run with it. Typically there isn't a lot in it going one way or another.