Normal glass or tempered glass on this table top ? Pros & cons ?

I have attached a picture of my hardwood table. One end of the table is shown, because i didn't have the patience to remove all items on it and take the whole table. Basically, the design is the same on both ends of table, and the mid-section of table does not have any designs (ie. curvatures) but straight edged center section. A second picture shows the length, width and thickness of the glass top i want to put on it. I have decided to go with a "pencil-edge shiny finish" for the edge of the table top. I have the following questions:

1. I went to a pro glass cutting shop to order the glass, and the owner has been doing this business for 40 years. So i have to respect his experience. He says tempered glass will shatter, if i bang an object (like a heavy steel vessel used for cooking and serving later) against the edge of the glass top. I understand that tempered glass has a tendency to shatter, but i am wondering if it would be so easy to shatter it. (Note that i want the glass edge to protrude slightly - ie. about 1/8th of an inch - more than the edge of the table. This has been decided after my research on the web, and reading about other people's experience with glass table tops for dinner table). Comments from those with experience having a tempered glass are greatly appreciated.
2. The weight of the glass top will go from 114 lbs to 171 lbs if i increase the thickness from 1/4" to 3/8". The hardwood table has 4 legs on corners, and the center part has 2 leafs that are attached using a sturdy mechanism underneath the table. This is one of the high end tables from Macy's furniture - so the quality is good. But, i wonder if it can stand the weight of a 3/8" thickness.
3. I am considering ordering 3 pieces of glass, rather than one long piece. The advantage of this would be the ease of maintenance if i need to clean underneath. The price might also go down, with reduced size of glasses i would order as the 3 pieces. I will put them on top, and there would be 2 places on table where there would be a gap formed by the glass tops. These 2 places, i plan to cover with decorative table top linen to hide them as well as protect the table from liquid that may spill on the table. The linen would absorb the moisture, and after dinner, i can clean it up in case it is a big spill. The second advantage of this idea is based on the assumption that the reduced size of 3 pieces would make it possible for the table to withstand the weight of 171/3 = 57 lbs, in the center section which worries me. Comments on this idea are appreciated.

I have searched the net, and could not easily find a solution that directly is applicable to my situation. So, i am posting in couple of places, to seek input. Thanks for all feedback.