I am at D3 Defiance and it doesn't matter this year, but when I get my classes all equaled out I am going to start RS one guy a year that isn't going to get any playing time.  Now, any rules I should know about RS?  Like I know that I can only RS one a year.  But, anything else?  Like if I RS them are they guaranteed to stay as a 5th year senior? (That's a main question but any other info would be great).

Yes they will always stay for the 5th year. They will be listed as a Fr. the season after their redshirt, and you can "pretend" like you never redshirted them.

Also, after you redshirt them they will count toward the 6 per class limit of their new class, i.e. if you redshirted a guy last season you can then only recruit 5 freshmen the next season.

Ok, thanks guys