Usually 30 degrees or less. More will cause either a lot of pulling or scraping, both of which are not friendly. I have to be careful with this myself, especially on the wider razors and those of heavier stock. I test shave with every razor I hone and I have a pretty thick beard, so I can say with confidence that most of the time a new person is having trouble with technique. Whether to strop or not before a shave is your preference, but I don't know what air cargo travel does to a razor so I always recommend giving stropping a try. The other thing is that you should really get used to the razor before attempting a full shave.
At the end of the day, I never mind doing a rehoning for any reason, because getting the person shaving is the main thing.
Have fun.
Lynn