Radiator core addition cost???

just a suggestion here but instead of getting a third row added get the cores tubes made larger , and add more rows. in my stock 72 340 radiator i had thought to do the same thing as you upping to 3 rows. the bottom tank could not support it. the guy said let me fix it up the way he suggested. i went from a stock 70 rows (tubes) to just under 100 (96). so i had more cooling tubes right off the bat. then the stock cooling tubes are real small maybe 1/2 inch? he put in tubes like in an rv that are about 1 inch. difference in temp was about 20-35 degrees. my car never climbs on extended idles or highway runs. cost is going to be expensive either way. my recoreing was 375.00, but well worth it. everything bolts back and fits with no mods or special hoses to buy.