Puzzle,
Centaurs always a fun creation to work on i’m sure. I’m not a expert by any means but i’ll give yah feedback what I’d prolly do. I’d prolly have minimal skin to child(mc) turned on, and it appears you have ires at 1-2 which is good. I’d add another zsphere before the shoulder joint and knee joint. Move the zspheres around to get the back and front legs to see if by moving them would work out the topology issues. If not i’d use the xyz edit script that TVeyes made and play around with adjusting some of the zspheres ires numbers. Especially in areas your wanting to have more detail it will help. Though if your going to turn it into a 3d polymesh and not work with it in preview mode then you could just use edgeloops for more detail in certain areas. Also might want to add a zspheres for eyes,ears,nose, and mouth areas maybe.
Check out Jason Belec’s zsphere thread… http://www.zbrushcentral.com/zbc/showthread.php?t=21407&page=1&pp=15 which has a ton of good info. though it takes lot of time going through and discerning what you need from it. However he does add some specific points to my thread where he helped me and might be easier to get the information which is here… http://www.zbrushcentral.com/zbc/showthread.php?t=39892&page=3&pp=15 hope some of this info helps you. Looking forward to seeing more, keep working hard!!