Machine sewing leather is problematical unless you use:
A) an industrial machine capable of single stitch speeds that can handle 3-4 oz veg tans ...
Tandy has a pneumatic machine capable of this, a typical sewing machine is not...
B) some thin garment type leathers can be sewn on a heavy duty, professional grade dress makers machine...but these leathers are not suitable for hunting pouches generally...
Sources for 3 to 4 oz veg tans are plenty...Tandy sells cheaper sides, and even their better grades of Craftsman Oak was on sale a week or so ago, it may be still? Wickett and Craig have great stuff...you can search the offerings of Leather Unlimited and Herman Oak too...
tca