Well if you must shoot pellets this year [ I don't like them for several reasons, for one they are irregular I weight a batch of them and there was a lot more variation than I get with a powder measure] Then I would suggest that you try them this way
2 X50
3 X30
4 X30
2 X50 +1 X 30
This is the range in which a Triumph usually finds a accuracy load, Very few shoot well with 150. Lee
P.S. When you get ready to do some serious shooting get a can of Blackhorn 209