I have an Avatar G212H that I bought new probably 8 years ago. It had pretty thin wire originally, probably 20-22 gauge. I rewired it with 14-gauge wire, but it didn't make much of a difference. My '83 Marshall 4x12 really benefitted from the 14-gauge rewire. I don't know what Avatar is using these days.
It can be tough to guess from looking at the outside of an insulated wire, and I don't want to cut one of mine to make sure, but I got a couple Avatar 112 cabs last year and I'm pretty sure the wires are beefier than 20 or 22, but I don't know if they're as heavy as 14.
Just asking because I'm rewiring my 16-ohm Avatar vintage model with a DPDT switch so that I can switch it back and forth between 16 ohm and 4 ohm. I wanted to match the speaker wire I'm adding to the what's already in it. I have to say that the wiring in mine looked to be either 12 or 14 gauge. I had some 14 gauge which I ended up using, and I couldn't quite tell whether the wire in the cabinet was just a hair heavier or not. But I guess even if it was 12-gauge, my using 14 for a couple of additional wires won't make any difference. Thanks for the replies!
And, the downsides of lighter gauge wire become more significant the longer the wire run is. For something within a speaker cabinet (i.e, not longer than a foot or two), lighter gauge wire won't make a difference.