I love my 301 mounted in a desk made especially for it. The control is mounted inside the desk cavity, and my knee knows where it find it every time. But the 301 has the bobbin at the left side. There is a flap that lifts up, and I can easily change the bobbin. Drop in bobbins would probably not be a problem either. If you had a front change bobbin, you may want to make a "door" in the front that would lift up or out or open somehow to get at the bobbin.