the air hawks take some fooling with to get the air setting right and then they take some time to get used to. Ive had one for about 3yrs now and ride over 20K a year and they are worth every penny for me. only seat better was the zepplin air seat and that things 500bucks.
yea the hawk takes very little air. it's not an air cushiontype deal, just enough air to tell its there.,

 

I dont think changing the seat will help i have had different seats on 4 different baggers
what made me more comfortable was a lot a riding on longer trips
either you just get use to it or your butt get tougher but i dont get sore anymore
Mazz

 

Butts are like a$$holes,, everybody has one.... and there are a bunch of seats to choose from.
I've had really good luck with the stock one on the Heritage..Sucker fits my big A$$ great. Again other hate them. will say the stock pillion in 07 is pretty lame. that I did replace for the little wife. she loves the HD touring seat and pad on the sissy bar. Pillion is 3 1/2'' wider and almost 2''thicker.. Pad is bout 3'' wider and curves with the back instead of just being flat..
Can go 3-4 hrs easy, rest a little a go again, but as said above it took couple months to be able to do it when new.
I think they do break in to the rider and become more comfy as time and miles add up..
I've sat on a Mustang for a Heritage once and believe it would be pretty nice,, just so far haven't needed anything to replace the stocker..

I don't think it would be easy to find just the right one..It'd be nice to ride on them for a while before buying.

 

Rather than going to the trouble and expense of buying a new seat or fooling around with an Airhawk, I would suggest you consider sending the stock seat out to Mean City Cycles for a permanent, relatively inexpensive, and very effective fix. Many here have used their services, and I've never heard anything other than raves for their work. Worth looking into.