I'm not an epidemiologist, and don't even know what's inside an aspirin, but what matt had to say was pretty consistent with what I've been reading during this information overload on mixing vaccines.

Last week, a UK study called Com-COV, which analyzed combinations of the same two vaccines, found that people in the mix-and-match groups experienced higher rates of common vaccine-related side effects, such as fever, than did people who received two doses of the same vaccine.

The WHO also warns against people mixing and matching (see link below) which is good enough for me. It's just too easy to do things the right way without trying to outsmart the experts. It's not like we're ordering drinks at a bar:

Farang: "Hey bartender, I'll have two shots of Pfizer with a Moderna chaser"
Bartender: "Sorry we're out of Moderna, but we have a two for the price of one special on Sinovac.
Farang: Fuck Sinovac - I'm driving tonight.
Bartender: OK, then how about a Sputnic chaser and we'll toss in a free bag of pretzels.

https://www.reuters.com/business/hea...es-2021-07-12/