have a small hand and thumb going bad.
any suggestions on finding the best fit
If you mean a pistol, try a snubbie revolver with boot grips.
you have to try them for fit, before you buy them!!
You did not describe how your small hand may be interfering with proper shooting dynamics, or how a thumb going "bad" may similarly interfere.
That being said, imho, if you are looking for the most bang for the concealed carry buck [no pun intended] for a comfortable small-hand hold, and managable recoil, I recommend the S&W M&P compact 9 or 40. Both of these have the shortest trigger finger pull distance I found, in "large" caliber semies.
I agree with the honorable Mister LLE! haha
The M&P series is one of the best pistols on the market. The changeable grips fit even my wife's tiny hands when using the smallest grip. The recoil is dealt with in a manageable way so that firing it does not cause fatigue, I have shot many rounds through the .45, .40 and 9mm. All of these have felt wonderful in the hand and smooth through the action. With a weakened hand you want something that will be top of the line but not break you hand. Go with the Smith and Wesson M&P series 9x19 para. Best bet! And good luck!
I have a friend in Security out at the Power Plant. He ended up loosing his right thumb while planing some boards when he was doing Home Renovations. So he sold some guns and paid for the classes and went into Security. Being limited to 9 mm or 38 in security work here in Florida, he opted for the S&W 9 mm long slide. It fits his hand fine and with a two handed grip he can shoot with the best of them.
But the fact remains, what are you talking about? Revolver or Pistol?
I would of a Security and consulting company and we have a retired cop that has half a thumb due to an explosives accident. The gun he carries...S&W M&P 9