Advice
1) Never let an opponent use your cues.... period. Even if they don't beat you with them, they could damage your cue, and then you would not have it when you needed it most ..... duh!
2) This adjusting every set is just a loser whining. I am not in it to get to the middle (50-50 competition), I am there to make money. If they don't how to make a game, let them be the victim of their own stupidity. If you adjust every set, YOU WILL BE THE VICTIM OF YOUR OWN STUPIDITY. In the old days, no one adjusted unless one player was up $500 or more.
It is up to lessor players to COME UP, not for better players to COME DOWN. EVEN the very best players CAN NOT OUTRUN THE SPOT all the time (bad table, bad rolls, break isn't working, opponent gets lucky). Someone that doesn't factor in the X factors when making a game, will soon be taking money out of their pocket to pay.
A matchup for money is a WAR, make no mistake about it. If he had 50 men, and you had 150, would you send 50 of your men to his side just so he would feel better ... duh! (you are helping him to defeat yourself, and that's what you do everytime you adjust after 1 set).
==> Read the Art of War by Sun Tzu (regarded by scholars as one if not the best strategist of all time). It will change the way you think about the game, and help the mental side to your game tremendously.
Players THAT HAVE TO PLAY ALL THE TIME, and therefore make money matchups JUST SO THEY CAN PLAY, will always find themselves in trouble sooner or later. Be more discreet about your matchups, and you pick your battles, not someone else. Tournaments can be used to play some better players if you want, or even money matches that YOU want to. ANY PLAYING SOMEONE ELSE IS NOT PRACTICE (HOW MANY TIMES DO I HAVE TO SAY THAT!!!), IT IS A COMPETITION (TO SHOW WHAT YOU ALREADY KNOW). Think of other sports, do they play other teams for practice, NO, they play among themselves working on basic aspects of their game BEFORE THEY PLAY SOMEONE ELSE.