changing primers

This is my first post here, I haven't found an answer in the previous posts on this site so here goes. I haven't reloaded shotshells since I was a kid but have quite a bit of experience loading reloading rifles. What I would like to be able to do is come up with a primer that I could use for several different loads. I was looking at using Clays for light target loads and Longshot for all my heavier field loads in the BPI Multihull. I understand that the two different powders may each require a specific primer since they have different burn rates. My problem is that looking at the BPI reloading manuals for various wads identical shot weights and type/charge of powder require different primers. I know that in centerfire cartridges you can switch primers by reducing the powder charge and working up looking for excessive pressure signs. Is it safe to do the same with shotshells? All I'm trying to avoid is buying a thousand primers for one specific load that I'll probably only shoot 20-30 times in a year. Thanks