It seems obvious that your heart is set on a new gun, custom stocked to fit rather than modifying a factory offering to your requirements. Who am I to discourage this endeavour? Both approaches can yield your desired results, if Fossari or another maker is willing to make you a custom fitted gun it will probably be quicker, maybe less expensive and certainly satisfactory compared to buying a standard factory gun and having it custom stocked to your requirements. It’s a long slow road either way but the chronic lack of competent stockmakers in Canada truly capable of fitting a shooter and making a stock to suit makes this painfully slow in Canada, expect this project to take years and probably require some in person fitting wherever the stockmaker lives. As previously mentioned, the VERY first thing you need to do is to determine what the gun will be used for and what you hope to accomplish, most shotguns are not ideal for all purposes. You mentioned that you have a small stature with smaller hands and are looking for a more personalized fit. Agreed, a shorter stock alone is only one part of fit, all of the stock needs to conform to the stature and shooting style of the shooter. For instance, while a slender 5’ 2” woman will definitely require a shorter than standard stock, she will also usually benefit from higher comb/lower butt face, smaller grip, slimmer forend and reduced grip to trigger distance as well. Balance would be adjusted as requested and normally be part of the fitting requirements Some of these things can be modified into a factory stock, some can’t without becoming ugly. Do your homework, find as many capable Canadian stock makers and European gunmakers as you can, contact each with your requirements and request a realistic estimate of both cost and completion for your project. Then you will have a decent handle on the practicality of the idea. Many top level competition shooters go this route so you won’t be breaking new ground. No matter how you go about this it will be a slow and expensive proposition, good luck.