I've never seen a split the ball set up that far out. If it's out that far you can kiss your handle good bye.
15-20 feet max. Wood block/log on the ground with two small nails on each side to hold a clay pigeon next to the blade,, the block has to be angled back a bit so the clays don't fall off. A split ball will bust both clays. People will miss and bust one or the other clay, it's a high maintenance target.
Biggest problem is keeping the blade in the block, they tend to fall out after a while with ball smacking all around it.
Best set-up I watched,, the guy used a wedge and mall to cut a slot for the blade,, he had a scrap double bit with no handle and had a helper hold a steel rod in the handle hole so he could hit each side of the rod driving the blade deep.
If anyone has handled an axe or splitting mall, standing over a block and swinging down between your legs to stick the blade is a darn un-comfortable move!!
Keep the block small enough to turn upright for the set up.