Bullshooter is right IMO. With ball in hand you take the 5/10 combo as a natural cut to the left and you simply have to play soft top left to float the cueball off the rail and down table onto the rail between the 8 and 6/7 cluster.
You call the 5, which may go in, or it may hold up and block the only pocket the 8 goes to for stripes. If the 5 goes in you can nudge the 7 as a safe and use the 6 and 7 as blockers on the remaining balls and the guy has almost no real direct kick at the 9, the 3 and 1 become a royal pain in the neck for your opponent from there. He has to make the kick though or you are then playing the 6-9 combo and he is going to be buried under the 7 with a vastly worse kick and a loss of game without some kind of miracle hit.
Using the 5 as the blocker as you guys are doing leaves a fairly makable 1 rail kick on the 9, hit with pocket weight it leaves a short side shot on the 13 and shape on the 15.
AKA you better hope while you were looking at that freezing onto the back side of the 5 that you hit the 4 perfect and left it in the jaws so the 8 does not go.
With the floating of the ball down between the 8 and 6/7 cluster you are actually leaving a far harder kick for the incomming player, and landing is actually huge, you have alot of distance on going into the rail, bouncing, and comming out. Freezing onto a rail like that is far easier then trying to judge the weight to freeze on the back of the 5.
Keep in mind, in no way are you trying to nudge the 6/7 on the opening shot though, I don't think Bullshooter mentioned that he was trying to touch those balls in the slightest either, not sure why anyone would assume he was trying to hit them.