Hi, have you definitely got your centre line on point & is the weight you're adding dead centre? This would be my first point too check if the bait is leaning over to one side.
There are so many differing variations in lure design, be it, store, hobby, custom or hand made that too pin point why you can't always match them for action & weight would be a nightmare, if you think about it, store lures can be made from a completely different wood or material, such as plastic, some can be hollowed out have rattle chambers in them etc, different top coat weights, paints, ballasts the list goes on!
I would suggest making something you're happy with yourself, do your own thing and learn along the way, ask lots of questions on here & the guys will help out & trust me they know their stuff!
I was in a similar position too you a few years back and as most suggest you just have to try stuff out, if you do want to get as near to store bought lures as possible then maybe resin molds may be an option for you.
Andy.