Mullard EL34 Tubes best with Lowthers Cayin ta30

Have a situation I need a pair and have two Mullards a xf3 B4C3 and a xf4 B9F3 so need to get another to have a pair. So do I get a 3 or 4 and what should I look for to match them the best way possible. I am running a Cayin ta30 through Lowther DX3 drivers in Acousta cabinets Mapleshade cables Mullard 12au7 and Sylvania triple mica black plates 12ax7 tubes. Changing from Tesla el34 to the Mullards. Out of the two xf3 or 4 which is the better audio tube and or should I sell them individually and get some xf1 or 2 in a pair? Any thoughts would be appreciated. Thank you