Whats the right ball for me? :
Lets start with the basics. If you are strong and healthy without back problems, then I would recommend throwing the heaviest ball that you can manage. Otherwise a good way is to go to your local laneswith a friend and starting with 16 lbs house ball, hold your bowling arm straight in front of you and have a friend place the ball in your hand while offering support under your arm and see if you can hold the ball straight out in front of you for 6 seconds without unbearable discomfort. Do this until you find a wieght that you can do this with Then add 1 pound to that wieght.
Others say 10 - 15 % of body wieght but this assumes that everybody is within the norms physically which is not practical as far as I'm concerned, so I prefer my way.
What type of ball should I use?
What are your league conditions like?
Dry (for me I would use a white or blue dot for a tammer backend and coventional line.)
Short oil (a mild polished Reactive ball drilled to go long)
Medium oil(a Strong polished Reactive ball with half of legal finger wieght and Half of legal side wieght)
Flood(Urethane or hookingest reactive ball drilled pin out and high with max wieghts on side and finger)
You should also take into consideration the style of your game when choosing a ball ball reaction depends on the speed revolutions and rotation of axis that a bowler imparts on the ball.
I would suggest having your local pro shop owner operator watch you throw a game or two then he(she) can give you a better idea of what style ball you should buy and how it should be drilled. They know the best ball for the conditions and your style of game.