(ET) mower deck basics

[tbamc <tbamc gbta net>]

How 'bout some really basic stuff?  I'm asking regarding my E12M but 
maybe applicable to others?

1.  Should the bar that the rollers are on be straight?  Mine is bowed 
in at least 2 directions.  :-)

2.  When mowing, are the rollers supposed to be actually on the ground, 
or barely above it?

3.  I've read about welding a piece of angle iron to the top  of the 
deck to make it more rigid.  Can you direct me to a picture of this?

Thanks.
Thon