After looking at pros and cons I decided to go with a stepped stud,
Mainly as I could bottom it to lock it in,
I was concerned that an insert could work loose as the covers will be removed for servicing.
No photos of the next bit as it happens very quickly,
When everything is at the right temperature the seat goes in,
You only get one go,
If it doesn't seat 1st time you get the welder out and start again
No probs here though
There is a couple more things to do on the heads but for now they can go for blast cleaning,
Always better to get the seats in before blasting
Got a bit done today,
The engine got its final clean
New oil bypass valve,pressure relief valve spring and new mains
Then in with the crank
No pics as I have to do it a bit sharpish
Plus a few trade secrets