the g-sight/pink rhino cartridges work well, but are disposable to a degree. Ie they wear out but not unreasonably quickly. They can be helpful for certain training, but come with the possibility of to much target focus vs sight focus particularly for those running iron sights. they are good...
if you like the size of the 365, also look at the hellcat/pro, shadow cr920, the glock 43/48. capacity and hand fit will likely be deciding factors on this choice, also consider whether you want the option for a red dot
I have used a neoprene belly band from amazon and it works ok, not good for training but fine for a small to med gun in certain situations. be sure to consider the retention mechanisms. Some are not very easy access, ie velcro vs snaps vs magnets. do you want more security or easier acccess...