looking for a little help here. i noticed that roto has a nice lineup of balls for drier conditions. i bowl in a house with older synthetics second shift. very little to no oil in the heads. first shift is junior adult league with varied skill bowlers throwing who knows what everywhere, so the back end is inconsistent at best. have a pearl sonic x, it gets through the heads just fine, but does not finish. looking at mercury, neptune, and venus. what might work for low end tweener, high tilt, low rotation angle, 14-15mph, right handed old man?