This doesn't actually give you a lot of choices buy it will make the type bigger.
Go to PC Settings, select the Display tab, at the bottom there is the More Options, option.
Set it to Larger and the type on the Start Menu will get a lot bigger.
I'd rather have something in between but that's probably coming in the future.
Added later, you have to go to the PC and Devices tab in PC Settings.
Then select the Display.