Recently purchase the following balls at a swap meet. All are in good condition and have no track worn. Storm Flame Blueish Green in color, Columbia 300 Classic Rock TEC2 and a Columbia Scout/R Particle.

I am 67 and have a 198 average for the past few years, bowl 2 leagues only at a Brunswick center with standard house shot and synthetic lanes and I am a stroker and roll a Track Stomp and a Storm El Nino Wrath which are about 4 years old. With the above information would appreciate help on the following:

Are any or all the balls I purchase worth investing the $25. per ball to replace the finger grips and plug and redrill the thumb? Any or all suitable for today's lane conditions? Fill any gaps I have on the 2 balls I currently use? I realize the drilling of the balls would be of utmost importance as to the answering of these questions. Any and all response will be appreciated.