Maybe it would help you to note the position of the latch when the bobbin case goes in. Right now my 301s are in their cases, and I don't remember, but I think it might be the 9 or 10 o'clock position. Once you identify the position, then the next time just get the bobbin positioned that way before you try to insert it.
My Pfaff 130 has a hole in the front of the wood cabinet for me to insert my hand -- I can't even see the area where the bobbin goes unless I tilt the heavy machine back, and I only do that when I am cleaning it. Again I know the position of the latch as compared to a clock and reach in with the bobbin that way.