On an ap1 what would you use to ditch the PCV/replace the connection?

I already have an overflow for coolant already which is good and i have a catch can but just need to change it to two inlets with a breather

 

Use a plastic or metal barbed elbow, just check diameter to get snug fit.
This is from a Swedish dealer but just to show what I mean https://www.do88.se/sv/artiklar/boj-90-grader-13mm.html
Check the construction on your catch can as well, not all are made to accept inlets.
Also most are usually way to small and with useless baffle system.
Here are some examples of well constructed universal ones https://www.nukeperformance.com/cate...oil-catch-cans

 

struggling to find a dual inlet one in the uk apart from the nuke which is to big for my bay. There is one on eBay but only hold 150ml but assume that’s ok as long as I monitor it regularly

 

If it's only 150ml then it probably just going to blow straight through, you could always go for two smaller ones instead.