It's a two part-er.
First, I love how hickory turns. I don't know much about the specifics of the wood between shagbark and plain old hickory; however, they both have a nice contrast between the pale almond colored sapwood and a light reddish-brown heartwood. (I've seen the nice mix between sapwood and heartwood referenced as calico hickory. It is my personal favorite for tool handles and I always try to pick out hickory boards that have some mix of sapwood and heartwood. It should make great looking pens!
Part Two, Although there are many great suppliers that are members of IAP and commit heavily to the craft, my personal go-to supplier is
Exotic Blanks from Racine Wisconsin. They carry many companies products as well as some that are of their own design. Ed Brown, Dawn Kizer, and their associates are top tier for customer service and all around pen turning expertise. (I think the kits you are referring to are likely
PSI Slimline models.) Exotic Blanks carries these along with many other variety of slimline type kits. For slim ballpoint pens my preference however is the
Streamline. Like me, it is a little thicker in the middle with a slightly larger center band so it does require different bushings (unless you are turning between centers without bushings).
Great looking first pens by the way, and of course, welcome to the IAP community! - Dave
PS I am also sending a private message to you following this post. Look for it by clicking on the little envelope at the top of the page next to your IAP username.
Dave