Looks like you can play the 4 at the 8 with a little speed. Follow the cue to the long rail. If the 4 hits the 8 reasonably close to making it, then the 4 should come up and loosen up the 15/12/10. If it misses the 8, then the position should be protected still.
My first thought was the stop shot on the 15, so if I didn't like the above, that's probably my shot.
This is my first and most likely selected shot from your WWGD series.
I would back-cut the 4 ball using pocket speed, but plenty of draw and a bit of left on the cue ball. My two main objectives with this shot would be to put another ball down by my hole and leave my opponent with hopefully a game losing decision.
I've left a very low percentage back cut for the other player, he also has to decide if he just going to slow roll it and hope to duck behind my up rail cluster, or hit the one ball firmly with confidence and barrel though my cluster.
That simple 4 ball shot should lead to 3-5 balls on anything he does aggressively and fails.