I have no experiance with Trail Boss powder, but don't know of any powder that a 357 will not handle 4 grains of without pressure problems.
I would shoot the loads you've made in a minute if they will chamber easily and if the cylinder turns freely, which it will because your ammo is under the MAXIMUM OAL loaded length. MOST bullets produce less than maximum OAL length, and it doesn't matter so far as safety. Max length is needed to minimize pressure by supplying maximum powder room to make the powder burn slower and or provide space for more slow burning powder. And to get the bullets closer to the rifling for less jump, which causing striping with heavy loads.
