Or is it better that I fumble with a brick AIP in mid flight?
No, there is a strangely archaic practice known as 'Thorough pre-flight planning'. Though strangely out of favour in these 'must have it now' times, it used to serve us very well in the old days. In the case of an emergency, the word 'Mayday' seems to concentrate the mind such that callsigns don't really matter. As to 'doing' an emergency, the mind boggles.