You’ve shown pictures of those before Harry. I thought it looked like a good idea so I made one like yours that attaches at on the bar stud. I used a piece of fiberglass rod from a bicycle flag. It worked real good last winter when I was dragging logs out’a the snow and up into the yard where I was working in the open… lightening fast! But when the snow melted and I started working back in the woodlot again it didn’t work so well. Darn thing was always getting caught on some brush, branches, saplings, weeds and whatnot... and it’s kind of a pain when starting your bucking in the branches at the top end of felled tree. Another thing, if you can’t work right-to-left it becomes useless… and I couldn’t come up with a secure and convenient way to mount one to the left side of the saw.
I still have it though… hanging in the shop.
Oh... and one other thing (but I worked around it), it won't let you lay the saw on its side for refueling.