Hi Stormin
If you look along the bottom edge you should see a hollow from tip of ploughshare to the heel, if not the ploughshare is worn you may have to add a bit to the ploughshare at the leading edge, not a lot just enough to give you suck this help to keep plough in ground
The best way to do it is lay plough on side run a level along the base from heel to toe slide a piece of flat bar down ploughshare till it sticks below level about half inch should be enough tack it on check then if happy weld it on
Hope this helps you.
Keep going and you will be coming to our fun day in Perth this year
George S