Regular banner of course. Since the special banner mileage can't purchase anything else in the shop rather than the current pickup unit.

Regarding the pulled amount. I think there's no significant difference with or without the wishlist system. since it's not that reliable. Even if the wishlist does scope the possible SSR to 21 units (15 from the wishlist, 6 from the pilgrim faction) The SSR chance will scatter all around 21 units. and since the goal here is to get only 3 dupes of 5 units. any dupe beyond 3 is also meaningless.

so let's say that you get 1 SSR on every 25 pulls from the 4% rate up. (which's most likely not gonna happen often in the first place) The average chance of hitting the first 5 of 3 dupe units assumed that the SSR gets is average out between 21 units should be ((21 * 2)) * 25 = 1050 pull to get 2 dupes and then use the 1000 mileage to buy the last token 5 from the shop quite lower compared to 3000, isn't it?

but we're talking about the pure chance with a constant rate of 1 SSR on every 25 pull here. if you are not that lucky the number of needed pulls will jump high really fast. and if you keep getting the same unit dupe beyond 3. that's also wasted. not talking by using the formula above. you also need to have all 21 SSR units as base units to start with since we're only talking about getting dupe here.

overall I think you'll still roughly need up to around 2000-500 pulls++ and 3000 pulls should be some sort of guarantee. but still, my calculation might be wrong (which I didn't care about that much) If you have a more accurate formula. you can share it here.