Riding Bareback? Should I?

I've had my horse Fletch a year now, and during that year his weight has fluxed up and down, more recently he has been out of work lame and has gained weight, which means his saddle doesn't fit. Fletch is a great horse to ride but when his saddle doesn't fit right he just flips out and becomes very dangerous! I've tried lunging but he just go's insane, and i really need him to work his weight off! (he is on a diet also) I was wondering about riding him bareback? Because that cuts out the saddle, which pinches at the moment! But I'm not sure, I've ridden bareback before but not on Fletch! I want it to be safe and nice for both off us! I don't want him to be nervy and bolt or being silly! So just any advice or tips? thanks! btw Fletch is a 17 Hh throughbredy/coby cross! (His half brother is Skip two ramiro!)