1.  Tile too close?
I have heard plowing in tile say, 30 ft spacings......40, 50 etc.

Lots of discussion about "tile being too far apart"...............so, can tile be "too close together"?

I am not talking about 5---10 ft..........but what would the problems be if tile were laid 30ft apart, when 40 would have been sufficient?

FWIW......I don't see a problem...........but I am not knowledgeable enough to be a pimple on a good tile guy's tail.

2.  For laterals......
Wouldn't 3" tile be sufficient enough in most cases (hillsides, relatively dry areas) to be laid in as laterals, as compared to 4" or larger?

(A "lateral" to me is a run that has no other lines hooked to it.)

Anyone put in 3", and then regretted it----------and if so, why?

Thanks.