Digital BW, The Print

First of all I'd like to say that this is a great group! I have 
learned so much about B&W digi-printing. I will be having a solo 
exhibition at a major corporate center next year where I will be 
displaying my B&W prints. With your help, my prints should be 
outstanding. Now I have a few questions for the group:

What is the reason that you convert an RGB image to grayscale then 
back again for B&W printing purposes? Is this only for scanned negs 
and prints or would it be right for digital RAW images also?

I have PS CS and am doing all post-prOcessing in 16 bit. Is it 
required that I convert to 8 bit prior to printing or will my printer 
(Ep 1280) print at 16 bits?

And what is "Dot Gain" and how do I work with it within PS for better 
printing?

Thanks
Terry Lyons
www.TLphoto.net