I have good luck with 1.45 prime and 1.5 suck at 40 (MakerGear M2 machine/hot end)
I think this is hot end and machine dependent. Also I've found with summer here in the states, the filament absorbs more moisture and boils out messing up the retraction. This is very noticeable using nylon.
I typically mess around until I get good results.
You can probably find the g-code where the retraction occurs and do an experiment by changing the suck and prime values. Maybe extrude 10mm, then suck, then prime, then pause to observe the filament. You could play around until you don't see any filament pock out after the prime command.
You have to watch out not to prime too little as if you have many reactions it will retract the filament out of the hot end. I had 1.8 suck and 1.45 prime and my filament retracts out on me.
Adam