If you want to do a sub hour for a non wetsuit ironman swim that is accurate, then you would need to go like 20x100's on the 1;20 holding under 1;15 for SCY. You can add 6 seconds for SCM and about 8 for LCM(1;26/1;28) And that would be about minimum if you are very good in the OW and a great drafter...