Well, now that you mention it, yes. When it became around 3-5 cards per stack it was quicker to use insertion sort. I found out, that like computers, it's ultimately a tradeoff between desk space(RAM) and stack iteration (CPU) by me.
I haven't tried radix sort - I'll go try it today and see how well I do. Nope, I don't do selection sort either, since it's quicker to perform insertion sort when stack size gets manageable.