Thanks for posting that Tom.
Building a Bombe is no small undertaking and I would hate to see you mess up the finish. Building it is only half the job. Not knowing what your skill set is, what materials you have access to, and what you are comfortable doing, makes it difficult to give advice. Plus everyone has different ideas of what is right and wrong and good and bad.
After looking at that attached article, I have some thoughts that may or may not help. He starts by sealing the wood which is fine. But then talks about a wire brush and 400 grit and walnut husks for color. Sealing the wood, in theory, is to get the color to absorb evenly. To much of it sealed and no color gets absorbed, to little sealed and the color gets absorbed to much. Wire brushing the wood after it being sealed? I wouldnt do that. What if you expose new unsealed wood then the color hits it and you go dark? Sanding with 400? you are just burnishing the wood making less color get absorbed. Walnut husks? never. Everything I do needs to be predictable and repeatable. You also cant adjust anything color wise with that hence the different color crest rail and splat in the photo. Go to W.D. Lockwood and order a few colors. I get water stains from them. Your stain is now repeatable and can be adjusted. Whenever I have sealed anything, water stain rarely penetrates the way I like or better yet what my clients want. Especially after something is stripped. I will then usually use a pigmented stain(depending on what it is) or usually alcohol dye.
What I wouldn't do is sand the case past 150(depends on wood figure), or apply water stain directly on the case, or use walnut husks. I also dont think the oil bw coats does anything and it does not help with adhesion. I would be careful with orange shellac as I have had it go to "orange" . If you are going to glaze anything or highlight areas/cracks etc. Do a test sample if you are using shellac. I use Mohawk products a lot and some of their products dont work with alcohol based products. In sanding shellac- use 3M gold 220 or 240.
Can you pad shellac? if so, you can color the entire piece this way with tinted shellac.
Hope this helps.