The most important thing to do first and foremost, is to check the height of the liner above the block as I would always bore liners in the block. Over a period of time the gasket at the bottom crushes into the aluminium and the liner sinks. If the liners have already sunk, they need taking out, cleaning and new gaskets making before then putting back in and rechecking measurements.
The liners need to be2-3thou above the block before you start reboring.
Somewhere on this forum, around Christmas 2014 there was an article on the building of my 3C Flaminia engine, covering all this. I still have the clamping plate I made which hold the liners into the block. Let me know if you want to borrow it. 07970421633 Dave Gee