I've used blue silicone on mine, both sides of both gaskets. They always seem to form a leak after several years on the upper drivers side, lack of bolts there I think. Shows as a seep and antifreeze residue. The better form a gasket stuff from Toyota is probably pretty good. Used a simlar product from Ford on oil pans for the 40, and I-6 Bronco engine many years ago. No leaks what so ever, good stuff.
I also use actual permatex thread sealant on a couple of the bolts for the water pump. I think it is the lower couple, can't recall. But these bolts pass through the block and into the water jacket, they can and will leak around the threads. I'm pretty sure factory manual indicates this.