How well does the belly band method secure safeties and triggers as compared to a holster? As long as it's secure, the P938 fits well. If not, you might want to go for something with a longer or heavier trigger. Sig P239 is a nice gun but kinda big and not great capacity. I also liked the CZ PCR suggestion, or a CZ RAMI.
Beretta PX4; 92FS; 92S; 8040G | Sig Sauer SP2022; P6 | Glock G19 Gen4; G23 Gen3| Colt Python 4"; 1968 Detective Special 2"| Smith & Wesson M642-1 | Ruger LCP; 10/22 | Daniel Defense M4V1 | Remington 870 | Alpine M1 Carbine | Steyr M1895 |1943 Izhevsk Mosin M91/30 | Walther PPS