Hi Ghost. I see we have no answers to your question so I hope this is of some help,
As for a tutorial I feel that may be taking things a little too far. Other than that I will give you the rough outline of how to go about thing in sequence but I will start with your screw question. The screw that you are describing is the traditional type of wood screw that was made as one off screws by a gunsmith on a screw cutting lathe, using a single cutting tool with one 45 degree profile which was ground to this profile by eye so it looked right to the man (I have seen many differing profiles). This traditional handmade shape is still produced today by specialist makers for the gun industry. But in the end any modern wood screw of the correct length and size will be fine.
Firstly compare the old pad mounting hole spacing in the stock with the ones in your new pad. The chances of them lining up will be slim but it has been known for it to happen. First see if you can reuse one of the holes if you can it is good practice to plug the other with a small hard wood plug, if it is not possible to reuse either hole plug both. At this point I line a ruler with the centre of each of the two holes and draw a pencil line which will become the centre datum line for one or the two new mounting holes in your new pad. Today there has been a trend to ignore the traditional way to put screws in to timber and I am guilty of this myself, we just push the point of the screw into the surface and drive it in and in my case with an electric screwdriver. You must not do this with the gun screw you describe, a screw core clearance hole must be made or the screw will act as a wedge with two wedges in a straight line splitting of the timber can happen. So for all gun wood screws measure the core diameter and drill a hole in the wood to let the core of the screw freely pass but allowing the threaded portion to cut into the hole walls.
Next place your new pad on the stock and adjust the pad to wood fit and try to keep the pad in the same position each time you move it by aligning the holes in the bad with the hole positions in the stock.
When you are satisfied that the wood to pad fit is good you should then fit the pad in its final position with the screws. A lot of pads have screw clearance holes but they do not go as far as the outside of the pad they stop quite close to the outside surface, to find where they are put a screw down the hole from the pads base and you will see it put a bulge in the rubber. To allow the screw head to pass through the pad I cut a slit in the rubber with a very sharp blade, it is a very good idea to lubricate the rubber around where you have cut to allow the screw head to pass easily without damaging the rubber leaving no signs of the screws entry, other rubber pads may have screw covering plugs to hide the screw heads. Finally you remove the excess pad down to the wood taking your time, some people use a grind stone others use a belt sander this sounds like a simple operation but it is far from that one slip and you can remove wood very quickly.
Just my thoughts! From the question you have asked I feel that this is your first attempt at fitting recoil pad to a gun, so dont let this first time effort be on a very expensive gun because you dont want to have a learning curve on a rich dark and beautiful piece of Turkish Walnut do we!!
What I have told you is the basics and may be some other members will post how they go about things because there are as many differing ways of fitting a recoil pad as there are guns. And the more pads you fit the easier things will become
Good luck
Damascus
