Integral Valve Guide (Broken Boss) Repair Options

For your kind of build I'd clean up those broken guides and run them- fresh valve job and I would hope that the machine shop checked or did the guides
maybe blend the bottom cut while you have them apart
want to spend a little money I'd cut the guides for viton seals or did you say you have teflon
Teflon's too dry for me and unleaded but YMMV
Is this a roller cam magnum motor? or what
machine shop set up the springs? or new springs?
If it ain't broke don't fix it
RT is a nice head