The only spec you need is what weight ball you feel comfortable rolling. The Viz-a-balls are plastic balls that are designed not to hook. Because these balls are such low friction, threre is no need to worry about any details such as top weights and layouts. Unless you are bowling on Sahara like conditions or can impart a ton of revs on the ball, these balls simply won't hook.
As stated above, you need to go to your local proshop and have the operator order the ball in your desired weight. Depending on which wholesaler he is using, it will take 2-5 days to receive shipment of your ball. He will then measure your hand and drill your ball.
If you have never had a ball drilled for you before, keep one thing in mind when choosing a weight. A properly fitted ball will feel much lighter than a house ball in the same weight that you grab off of the rack. This is because you don't have to squeeze a properly fitted ball to hold on to it. Most men choose 15-16 pounds. Most women can handle 14 pounds fairly easily but many choose weights a bit lighter out of personal preference.
[This message has been edited by The 5200 Acres (edited 10/9/2006 10:09a).]