. . . something customers can select frome a list of various kits and blanks?
There is some good information above.
Your approach in the quote above "can" work, but it can cause a lot of headaches too. People want to see what you produce and how well you produce it. The quality counts. It is not a matter that you made a particular kit with a particular blank, it is how well you make it and the fit and finish - if you want to continue to sell.
IF you offer "choose your kit" and you will make if for them, there will be those that will look the kit up and then ask, Why are you asking $50 for a $7.95 kit and a $5 blank? You will be getting into a non-winnable argument, and then unwanted feedback comments. There are those that sell pens in flea markets and local craft shows for $10-$15 or so, but they will not get repeat customers. Don't base your selling price on those.
IN addition to what John asked - How do you make yours? How do you measure the sizing - by the bushing size, or by calipers? How do you finish them? A good coat of wax, or oil based finish (Tung Oil, BLO) or CA or Lacquer, or other? By and large, most people here will help you if show them what you can do. There have been quite a few that started simple, became good at it, and have advanced to own reputable businesses. The people here are very good with helping others advance in business and creativity. But there is a trust built through postings here.
Going into business is more than just offering a list of business decisions, it is about the planning, tools, product and production.
Product choice, production, web site sales, photography, tools, finishes, extraneous material, shipping, taxes, business license, - any one of these can take a full page or more to describe. We have seen it all here for 16+ years and it is more complicated than it appears on the surface.
Please take the time to let us help you. No, we do not want to steal your idea. It is not original with us.
Although there are a few new ideas that come our way each year in creativity, there are rarely new "business" models being developed. A couple of years ago, there was one guy that wanted to sell to pen turners so that we would not have to make our own. That was original, but it did not make sense. We would enjoy offering help, and as said earlier, there are pages written here on starting businesses. We do like to help, but more information would be helpful.