Changing valve guides yourself

This is the first time I have tried to change valve guides, so please take the following with that huge caveat. Initially I had not planned to renovate the cylinder head on my 1959 Triumph Bonneville. I knew the valve guides were shot and I even had a piece of carbon that has made a dent in the seat and valve on one of the exhaust ports. But as I was in for quite a lot of money on the bottom end…