Since I always work out by myself and don't want to bother anyone else, I don't use a bench press, I use the bar that slides with the safety catches that is referred to as a Smith Machine on some web pages. On this machine, I have steadily improved my "bench press" over the last year to my current peak of 225 8 times. Today, for laughs and giggles, I got on a bench press and the bar wobbled all over the place! I realized that I did not the stabilizer muscles (not to mention the technique) to lift more than 200 (a guess, as I did not have a spotter).

I want to continue to improve my BP. I can and will improve the technique and can continue to improve chest and arms with the Smith Machine. How difficult is it to develop these stabilizer muscles (delts? back?) and what would be recommended to develop them, other than just doing more bench presses?

My thought at this time is to continue using the Smith Machine with the heavier weights (225 +) to continue developing triceps and pecs (which my wife and her friends love but combine that with lighter weights and occasional spotted heavier weights to develop these stabilizer muscles and any specific exercises for these stabilizer muscles.

Suggestions?

Do free weight barbell sets first, then smith machines to really isolate.

I think that you should just do a switch to the barbell, it wont take that long to get the hang of it and stabilising the bar. You wont lose size because of it you will probably gain if anything.

Or you could use dumbells, safety and freeweights.