Been using these for a year or 2 now and what I do is
Removing the red / black bungs..pull red flappy bit off push the middle through ( this comes out if you fill it with water ,turn up side down and open the tap as it causes a vortex)and then get a piece of string and wrap in around twice the Bung between the Bung and keg ( if that makes sense ) , then pull the string gently And the Bung comes out , I use the grey 2 piece bungs and they just pull off , I don't use Vaseline with these I simply twist them on and never had an issue in about 50/60 kegs this year
I use a Cooler for these from Germany and a party star , you can use the red black bungs with these easy enough, hob goblin have started to do a different Bung now and they are a pain to get off .still working out how to do them with out damage , done 4 with cutting bits of it with side cutters although I buggerd one up and had to throw it
I prime with 13/14 g of sugar per 5 litre kegs and it is gassy for the 1st pint or 2 ( I like fizz though) but I don't use co2 for the 1st few , I put the co2 in when it starts to slow , I also use 8 g co2 in a 16g Home made holder as I find it easier to get 8g .
Hope that helps someone