Throttling is a wonderful feature to get rid of during a migration. You have the need -- the need for speed. Throttling can sometimes be the annoying speed bump or rumble strip that at best slows you down and at worst halts your migration.
Fortunately there's a good guide to how to disable using the user interface on Office 365: Disable EWS throttling in Office 365 – Exchange Online
We don't re-do work that's already been done -- this is a good, straight-forward guide.