This won't be a popular reply, but since you are intent on having a good paper trail for the oil changes in case of future warranty claim(s), I would say give the dealership your oil change business.
I say that because...hold on...BRB...
Okay, I'm back, sorry, there was a mob of BITOGers outside carrying torches and pitchforks and clamoring for my hide...
Anyway, the reason I suggested to give the dealership your oil change business was exactly for the reason you want to keep a good record of the oil change history - in the event of a future warranty claim. Although I'm saying it not for any regular warranty claim, but for those rare, once in a lifetime strange warranty claims where the decision to approve the warranty work could go either way...50/50 chance you are denied or approved.
Let's say some component goes out 1 month outside of the factory's warranty ended or 1000 miles past the end of the warranty. If you have a demonstrable history of bringing the vehicle into
that dealership for regular service, they are more likely to work for you rather than against you if you request a warranty claim on said component.
Maybe it's a free tow into their service center or an upgraded loaner car for an extended time period. There are any number of things they could do to make it worth your while for using them for your regular maintenance.
Just a thought, and it's not without precedence I might add. So think it over before making your final decision.