I didn’t see anything that required rebuttal. Unless I missed it, Mytton hasn’t responded to this thread at all since he posted the first one. This is unusual, I hope he is just busy and is okay.
This is definitely my own conjecture:
Going from memory, Ruth Paine has said that she doesn’t remember seeing the rifle in the belongings she transported to her house from New Orleans. And that she suspects the rifle could have been in the duffel bag. That makes sense to me. LHO could have disassembled it (so that less of it would stick out of the top of the duffel bag) and further concealed it in the blanket before he packed it into the duffel bag. At some point the disassembled rifle (in the blanket) was removed from the duffel bag and placed on the floor of the Paine’s garage. If this theory is true, then LHO should have had a pretty good idea of how long to make the paper bag in order to conceal the disassembled rifle while transporting it into the TSBD.
Sealing both ends of the paper bag is your idea. It just doesn’t make sense to me that it was necessary or desirable.
Your conjecture fails to take in account that Michael Paine said he removed the blanket with content from Ruth's car and placed it in the garage. If you believe that the rifle was in a duffel bag, wrapped in a blanket, then what was the camping equipment that Michael Pained said he thought was in the blanket he took from the car?