The temperature you achieve without additional heating equipment is primarily related to batch size, the more must in one vessel, the hotter it gets. If you want higher temps on your next batch you could fill one brute a little higher than the other. As mason said, there is no absolute right way, some like the high temp early in the fermentation to get color and body without extracting as much tannin yielding a bit more fruit expression, high temp late in the fermentation when significant alcohol is present tends to extract tannins from skins and seeds possibly ok for long term aging. All of this depends to some extent on the type and maturity of the grapes in the first place, the type of tannins present etc. Some winemakers are looking for more tannin and some are looking for more fruit to get balance.....this is a crazy hobby, but I suspect that's why we're all here.