Just a thought. I would accept that Paula Radcliffe 'led' that Olympic 10000m for around 9000m, right up until the last lap when the three East Africans left her to jog in for 4th. I struggle to say Samir 'led' the race when he did an idiotic max effort for the equivalent of two laps of a track and then let the winners beat him by 25 mins. In other words he wasn't in the race In any meaningful way. Am I missing something?
I would be inclined to focus on VLM then find a half 6-8 weeks later. Better likelihood of two good results in my opinion, and less likelihood of screwing up the reason you have been grinding out all of those 20s.