Welcome to the forum! I haven't built this model, but if you search for build logs of the Syren 1:24‐scale Medway Longboat, I think you'll find a lot of helpful information. Syren's kit is a larger-scale and more detailed model of a very similar vessel, and it was designed by the same person, Chuck Passaro. He's active on this forum, and has a very detailed Medway Longboat build log that might be helpful. Syren also has its instructions free for download, and it probably would tell you what you need. The only thing to keep in mind is that, with your model in a smaller scale, it will be more difficult to strop the blocks and make other parts of the rigging. There are also plenty of build logs for this exact kit, some of which may show in detail what you're after. Best of luck!
PS: Syren's guide for stropping blocks (available for download on its website) is also extremely helpful--it doesn't quite replicate how actual blocks were stropped, but it shows a way that's pretty easy and looks good.
I'm not familiar with Dressel's book, but have marked out planking bands before in some of my own builds. How are you measuring the distances and how are you marking out the band locations? Before doing anything else, I'd triple-check that your measurements are being taken from consistent points on the same bulkhead/frame (something that I've certainly gotten mixed up on before), and using a material that won't stretch. For instance, string might stretch when you pull it tight around the bulkhead shape or to measure it, but a strip of paper or cardstock won't stretch.
JacquesCousteau's post in Rigging the boom was marked as the answer