Sending ttt for you in case a Cutie can help. Sorry I don't have the Brother.

I didn't realize that you could get a multi hoop for the 750D. Would you mind telling me how you use it and what type of bobbin thread you use in your machine. I am having trouble with the bobbin thread coming to the top and adjusting the bobbin doesn't help.
Any help would be appreciated.

I had dramas with the bobbin thread too. took ages to work it out. I now use Brother's 90 weight bobbin thread. Check out Ann's fix it page, it was a big help to me. The multi hoop has 3 sets of hooks on the side so you sew the top, the middle & the bottom in 3 seperate files. PM me if you want more info. Lyn. xx

I think the Brother 3100D most likely does accept the multipositional hoop. My old Brother PC8500D accepts it. I, actually, have used this hoop to stitch a single larger design that fits within its perimeter, rather than using it to just combine smaller or split designs.
Angel