The way that I understand dip hopping, you use a very concentrated hop charge, so for 1 lb of whirlpool hops, it would only call for +/- 1.5 gal of wort at 160. I was planning to split the whirlpool/dip hop and only use the 8 oz of LupoMax in the fermenter, which should be equivalent to about 12 oz. of T90, as they are concentrated (YV says to use 70% of LupoMax vs T90), so you only need <1 gal of wort. You shouldn't need to cool the fermenter, as the other 10+ gals remaining in the boil kettle will be cooled after steep, so the warm 1 gal in the fermenter shouldn't raise the temp too much. Someone asked why split, and I just thought that it would be a good way, since they recommend to use T90 in conjunction with LupoMax. I have had good success doing using cryo/T90 in combo and since I got the LupoMax and it is a similar concept (more resin/less vegetative mass). The dip hop stay in the fermenter throughout dry hopping, etc.
The Gigantic process is straightforward: load the late-hop addition into the empty fermentation vessel, purge the tank with CO2, then add some hot liquor at your target extraction temperature to create a concentrated hop tea in the tank. Hopping rates are similar to whirlpool additions—0.75 to 1 lb (340 to 454 g) per barrel—and a half barrel of hot liquor is used for each 11 lb (5 kg) of hops. Target temperatures are 150–170°F (66–77°C), and the hops steep for about an hour before the brewers pump cooled wort into the tank and pitch the yeast.