Great mod! Just throwing in my opinion here, I love the way it's set up now without having to complete massive momentum changes or wait for launch windows. It's something different from everything out there in that aspect, if you wanted something that didn't change your momentum you could just use one of the many warp drive mods that function that way. I think it adds a great gameplay mechanic with having to manually set up your entire network at appropriate altitudes for transfers. If you do change the mechanics to increase force to account for momentum changes then you should also add the ability to use the drives additively through action groups. But IMHO I like it the way it is now, since lower mass ships have lower gravitational forces applied at all altitudes thus requiring a good bit of thinking to get a network set up especially if you're doing resupply missions and have to optimize multiple variables (ship mass, cargo mass, fuel, beacon altitude, etc.)