Mr. Rims,  in response to your questions:  
1)  Talk to a reputable dealer who is familiar with the model you will be looking at.  Oversized is better than undersized.  With a bit bigger stove, you can get longer burn times.  If you go too large, you will have longer idle times which means more creosote.
2)  Others will have to chime in on that one.
3)  I have no opinion on woodmaster specifically.  However, it is NOT one of the "NO WAY JOSE" type stoves like Shaver or Wooddoctor.  I think the questions people looking to get an OWB need so answer are: do I want carbon or stainless steel, do I want forced draft or natural, conventional or gasser (state may decide that for you), expensive or affordable, dealer near or far AND is the dealer knowledgeable or just selling a stove.
4)  Do a lot of research on your brand.  Be VERY open minded.  When I got my stove, 90% of the people in my region owned 1 specific brand.  I researched and thought it was a terrible stove, and ended up with a different brand.  The reason everyone had the same stove, is because there was 1 dealer in the area and this was the stove they sold.  So, everyone just got that stove because everyone else had one.  
Good luck and feel free to go into each brand and ask the guys who own them what they like or dislike about their brand.