Digital BW, The Print

I'm a newbie to the group and to digital printing, and I'm confused
as hell ...  I'm learning a lot by following this group, and I
appreciate hearing from the knowledgeable folks here.  That being
said ...

What is BO printing ?  I know it means "black only", but what exactly
does that mean ?  At first I thought it mean checking the "Black"
box in the Epson printer driver, ignoring the "Suitable only for
text" warning, and manually setting the DPI to 1440 or 2880.  

It's clear from reading here "BO" also includes use of the after-
market inksets from places like MIS, which apparently use a small
number of inks of various shades of black. 

The first method ("BO1") I have used on my Epson 2200, and the prints
look pretty nice, but I can imagine the fill is a little "rougher"
in the highlight areas; these must be the "dots".  (Yes, I am very
far-sighted).  I still prefer the prints to those made using all 7
inks; the latter look fine under artificial light, but kinda a
gun-metal blue under daylight; I assume this is "metamerism".

The simple BO1 method on the 2200 only uses one ink cartridge, so it's
easy to see why it has "dots".  What I don't understand is why
one of the after-market inksets (like MIS) should be any more prone
to dots than a print that uses all 7 colors on the 2200, since they
have 4 or 6 cartridges with various shades of grey (as I understand).

Finally, given that I want to stick with the 2200 (since I want to
do some color too, and I don't want to buy another printer right
now), what course is best for me ?  How much worse are the dots 
using the "BO1" mode than when using the more broad definition of
BO printing ?  Should I try to do the Grey balancer thing ?   
Or hope MIS comes out with their inkset for the 2200 soon ?

Thanks for clearing of confusion and advice, John