Richard,
I am only giving my $.02 worth because I want you to be a happy camper.
For two years ('69-'70) I worked at a commercial trap/skeet range (Roberts' Shooting Park Elkhorn NE) setting/pulling trap/skeet for $1.50/hr. We used Blue Rock (no longer made) and White Flyer clays. Champion also makes clays these days. I have no experience with Champion, but White Flyers were well-made clays. White Flyer also makes bio-degradable clays (for more money). The older composition clays were toxic to hogs, but not to cattle.
I don't like the spring clip that fits over the dome while on the blade. When you load the trap, do it in the uncocked position, and cock it afterwards. It will save your fingers if there is an accidental release while doing so when cocked. We were taught very early to "swipe" the clay(s) onto the blade with the clay(s) shallowly cupped in the palm of the hand(s) over the dome of the clay, because one could never be sure when the puller would release the blade. Two hands were needed for doubles shooting. They were electric motorized traps which would reset/recock the blade immediately after release, and the blade mechanism would oscillate more than several degrees back and forth (to present the clays at different angles for the shooters) making it that much more tricky to load.
Check every clay before you place it on the blade. A good clay will have a dull "ring" sound when tapped against another clay. A cracked (even a hairline crack) clay will have a "clack" sound, and should be discarded. It's not fun to have one become clay "shrapnel" in your vicinity.
Good luck in your endeavor, sir!
Regards,
Jim
