The front end presents plenty of opportunity for improvement. The CB's forks use a damper rod system that typically feels too plush over round bumps yet too harsh over square edge bumps. A damper rod system doesn't cope very well for a wide range of suspension travel rates, i.e. the speed at which the forks have to compress and rebound for the bump. This system is one of the oldest, simplest and cheapest methods employed by bike manufacturers to provide us with dampening. There's a lot of written material on internet if you want to know more. Now combine a damper rod system with an under rated spring for your 220lbs and you are going to have a soggy front end that sags too much just holding up the bike and you, feels too soft diving excessively under brakes, but feels too harsh when you hit a square edged bump.
There are two common modifications to damper rod forks that are very effective at improving performance:
1. Insert an Emulator valve in conjunction with an appropriate spring to suit your weight and the appropriate weight fork oil. The damper rods are drilled out to open up the oil passage so that all compression damping is performed by the newly inserted emulator valve. The choice of fork oil weight sets the rebound damping. This is the traxxion dynamics cure. It's inexpensive but may take some fiddling around to set the compression and rebound characteristics that you want - trouble is that you need to remove the forks and change the fork oil if you want to change the rebound characteristics. To change the compression characteristics you will need to unscrew the fork caps, remove the springs and extract the emulator to adjust the valve. An alternate option is to ...
2. Insert a cartridge assembly into each fork. The fork is gutted and reassembled with a cartridge system that includes springs and both rebound and compression damping circuits. This method is more costly however all damping characteristics are adjustable on the fork caps to give you an externally adjustable front suspension.
If all this is too much you could achieve a significant improvement by simply upgrading the spring rate to something more suited to your weight and experimenting with different fork oil weights until you're happy. This would be the least costly method but may involve removing/refitting forks a couple times until you have rebound where you want it.
There's a few forum members who have made these modifications and you could search the forum as I'm sure that some did share their experiences with us. I went the cartridge inserts route fitting Andreani units and so far have been very happy with the results. This post explains a little about the project:
http://cb1100forum.com/forum/showthread.php?tid=12036
The stock rear suspension wasn't too bad for me as I very rarely carry a pillion. You already have a lot of information on rear shocks and I would has at a guess that any reputable aftermarket suspension that includes rebound damping with the mandatory spring preload adjustability would be better than the stock units. Good news is that the rears are a 15 minute job to fit. Be careful not to over tighten the mounting bolts as they are light duty and only there to stop the unit from sliding off its mount.
Have fun! Upgrading the suspension is one of the best value modification you can do to the bike which you'll appreciate every time you ride.