I will bring you a selection of express and 8.44 pellets to millride.
To do some test's you will need an indoor facility,I would say that sywell is the last place on planet earth to shoot group's.
You could order 3 tin's from inter shoot 4.51,4.52 and 4.53 that would be a starting point.
Just make sure they have a couple of sleeves of each when ordering,once you have found your pellet buy a couple of sleeves.
Of all the pellets I have tried express seem the least fussy , but they come with their own issue's.
About as much use at field target , as a life guard at the Olympic swimming pool.