Many bidders are conditioned to wait till the last minute and many, like myself think it's just prudent. To me, 7 days is ideal for an auction. I'll go longer only to give more time to get the word out to prospective buyers, especially with niche categories. You "definitely" need to do that, even if you spend hundreds trying to keep your name on the home page. You must advertise your auction at other venues.
If you don't already know, the featured option is a one time deal. The name will be on the home page until other featured names are added after yours. As other names come on line your domain drops down the list, then that's it The first time I used it my name was only on the home page for a few hours. If you want back on the list it's another $50. I haven't used it much. I'm not sure if it's different with the premium option. To be fair, I haven't tried the premium option yet, but I have used the $85 option. Some not so hot names stay on the home page for a week or more though. By my calculations that's at least $300 or $400 extra. Suppose you just have to go for it sometimes.