In the absence of such an instructor, if one keeps doing internal solo and partner work in empty-hand mode, instilling the skills, then how it applies to spear or other weapons will be clearer to see, along with understanding the technical differences and details of ma'ai, blade applications, and other factors compared to empty hand.
FWIW I brought two friends to bodyworks seminar earlier this month. Last Friday I taught the first day of our annual bokken seminar going over what are simply the basics of what we do. Both commented to me later that after the seminar much of what I (and others) had taught them during that workshop over the years and much of what we do with how we hold, move and use the weapon made so much more sense. It tied any number of things together including "being one" with the sword, tenouchi, swinging the sword not with the arms but with the entire body, and on and on and on. The way I've put it since I started down this path is that this stuff "informs" your movement. You really don't have much question as to why you do things the way you do. It just makes more sense, fits together better, and gives better results.