If you select 6 fixed...you will have 6 "roaming" if you select 8 fixed... you'll have 4 roaming... depends on what you wish to do...If you have a lot of feedback perhaps you you need to tune your system... if you find that you need more than 6 fixed filter that is likely the case. I find that as the volume of the performance goes up the speakers response also changes, and must be compensated for. I find that if I tune the system at reasonable volumes, and then get a really loud band that cannot/will not control stage volume and you find yourself having to CLIMB over them to a volume you are not set up for ... you will have issues...especially if they cup the mic head...turning the mic into an omni directional pickup device...
Every application is "live". You'll have to deside how many you need (fixed vs. live). I'll assume that you are a DJ, so you should not need need to set too many fixed unless you have major issues with your speakers or room problems. Try 12 total filters, 6 fixed set as Music High, then set the live as Speech and go with it. You may need to change things a bit but you get the idea.