Is it wise for me to do 4 half marathon time trials every 4 weeks, before a marathon. The first 2 being time trials the second 2 being tune-up races (that I still wanna race well)? I have a cutback week the week after every half. How much should I cut back? Anyone else structured their program like this before? Say, all out for me is 01:15, and marathon pace is 1:20. How fast could I expect to race these to peak for the Marathon well in the end.