Torch, Prestone makes both a "Super Flush" and a "Radiator Cleaner." The second one gets poured into plain water in the cooling system and stays in there for a while (can't remember how long), so it cleans a lot better. Might be something to consider.

I also like using a Prestone flush and fill kit to flush the cooling system out from the heater core hoses toward the front. You can leave the tee on there and cap it or just replace the hose you spliced into to install it when you are done.

I also try to do my final fill mix with distilled water rather than water from the hose to cut down on minerals.

Sounds like you should be good to go with a restored stock rad. Keep us posted.

John B.