I can give you a part of an answer.

I just spent right at $1000 on rebuilding the heads, plus a head gasket set, water pump (front and back halves), all the hoses, all the belts all the serp. belt idler pulleys, and a new timing belt tensioner set, and I did all the labor. Head machine work was over $400 of that total. Light surface cut, 3 angle valve job, 1 new valve, 2 new valve springs, remove 4 broken studs. And a new thermostat and coolant temp sensor for the ecu.

I'd adjust that some up since you have twice as many valves...

Not responsible for advice not taken...