I have flown lots out of both (YPPF,YBAS,YBRM,YSBK) and as you mentioned there are "local" style "rules". I tend to stick to the AIP which does not differentiate between the old GAAP and larger class D. I now always offer a departure report (was never done through training, and was unaware it was required until work) and most times they will accept it but the "metro D" guys usually sound a bit surprised, and with the others sometimes not requesting it when super busy. Not sure if that's what's meant to happen but, if they have you sighted in VMC I suppose it's ok.
I haven't flown VFR into a "metro" D since training but the D aerodromes don't require clearance via a reporting point and a radial/bearing and DME/GNSS or miles used instead, if equiped and able.
Unsure if that would be OK in town.
IFR at both just planned as per the AIP and should be easy enough. Direct once airborne might be easier outside of the metro areas depending on identification.
The metro D ground controller always seems to clear outbound via the run up bay (and I always forget to say that it's not required) and at the others clearance via the run up bay must be requested if required. That would just be because of the amount of training AC in town.
There's a few more little things but seems to be aerodrome specific rather then between the above.
I'm definitely not an ATC guy, they would have more to mention ild imagine, this is what I've picked up on the operational side.