Purchasing Best Practices - Low Volume, High Turnover

My company deals in small batches of high quality outdoor equipment / clothing.  One of the issues we have with NetSuite is that we can't use much of the auto-purchasing functionality due to long periods of not having an item in stock (which throws off auto calculate lead times, etc.)  This also makes it hard for us to use the "items to order" feature, as many products are a one time release (and clog up the list), even though there are others that we want to keep in stock all the time.  I am trying to set up a purchasing