The garage that services my classic cars told me that changing the rear main seal often helps only for a short time due to the missing asbestos... If I can mitigate all other leaks and this would be the last remaining one not too serious ... I wouldn’t fix it soon. From a short look there’s a spot on the floor under the front of the engine where there is non-flourescent oil. This seems the biggest one at the moment. And the first I will investigate closer.