...Something else about 'instructions'. Use everything available to you to gain information. As in, the picture on the box, advertising pictures, pictures of completed boats, anything you can find. Compare the pictures to the plans (if any) and the pieces that make up 'assemblies' (sometimes that takes an electron microscope and a crystal ball) to see what goes where and how.
Something else you'll notice is that no two boats are ever exactly alike. One reason for that is personal preference, but also, people interpret(sp) the instructions (or lack of them) in different ways with different results.
All of this doesn't justify crummy instructions, but it does help a little. Sometimes I get the feeling that 'they' think I was there when the original boat was built and the instructions are only to remind me of how that was...
- 'Doc

The motors included/recomended are only 'adequate', not the 'best' (whatever that means). If in doubt, over build [within reason]. No single kit can be made for all uses, so you have to customize for your use of it.
(I can make you a good deal on a chainsaw blade sharpener!)