Ummm, just cause it has 300 in the name doesn't mean that you get 300 channels. it all depends on how many channels you purchased when you purchased the
console. You can have more channels unlocked by calling
Strand and buying a password. Through this
system you can buy as many channels as you may need. Other thing of note is that there are Channels and Attributes on the 300 and 500. Attributes are used for attributes of MLs, so when you patch an ML, instead of using 25 channels it uses one
channel and 24 attributes. Along with this, you can se channels as attributes, but you can't use attributes as channels.
Interested to know what issues you had with assigning FX to subs, I have never had any problem with that.