Hey mate, i used To be a fellow high 20's handicapper like you and i was in a similar position to you. i.e my drives would slice and hook ocassionally, just generally not being effective of the tee is the vibe im getting from you. But anyway, i was out on the course one day and then this random guy joined me. But anyway he gave a srixon soft feel golf ball, and boy did it work! On short par 4's i was driving almost to the green, all of my drives were generally heading in a straight direction as well. One thing that you should know is that low spin balls will not completely eradicate your slice or hook, if you strike the ball wrong, the low spin ball will minimize the damage, if you will. Also, how high do you tee up the ball? Because my playing partner noticed that i was teeing the ball up to high, so i lowered my tee off and it worked like a godsend!
Hope this helps.