I am certainly no expert in this and some may think I was crazy in how I went about making the decisions about what you asked. My daughter and I kind of work together on some of these projects. We recently did a benefit craft fair at the vet tech school where she is an instructor where a part of the proceeds of sales were donated to an animal shelter with the maker keeping the balance. Knowing that the students could not afford very high priced pens, we selected slimlines, euro styles and comfort grips in different finishes from PSI to use as kits. I also had a decent selection of acrylics I got at a discount from HUT and natural wood blanks from an assortment from PSI. We discussed what we had and which blanks we liked/disliked but came to the realization that just because we didn't like one it didn't mean someone else wouldn't. So I just randomly picked out a number of blanks for each style pen, cut the blanks to size, glued in the tubes and then trimmed them up. Then I started turning out the pens for each style till I had them all done. We then took each pair of tubes and laid them out against the various finishes of each style, decided what looked best for that particular blank and assembled the pen. Some of the pens had identical color or wood type tubes but different finishes to the hardware of the pen.
We were really surprised at which ones sold in some cases. Although the sales weren't tremendous given our customer base, we made enough to have paid for all the materials we used, had a nice donation for the shelter and still had about half of the pens left over for another show that now were paid for in full. We didn't make a lot for our time, but the intent of this fair was to get donations for the shelter, so part of our time was also considered a donation as well in our minds. We are planning to use the same philosophy in making more stock of these kits and several higher end kit types. We will use higher quality, fancier acrylics and woods for the higher end kits of course, but we think that if the idea worked once, it should again.