Hi Andy,
you just need to glue up some holes. TD don't currently do any less than 6 hole pistons.
Again it's all down to personal choice, what feels right to one person may not do so to someone else.
To make pistons to suit everyone would be impossible, so its easier to make pistons with more holes and give people the option of gluing some up if needed.
I know me, Nathan and Adam all run different set ups to each other, so its good to have a play around and find what works for you.
