Wow, you have a lot of attachments and info.
I want to make pet beds for the local animal shelter and need to go through several layers of flannel. The buttonholes I have already made had a hard time and the buttonholes turned out awful. It may be that I need to do some other adjustments but am looking forward to trying the buttonholer for the Singer 99K. I haven't purchased anything extra to go with the Singer 99K, so this will be the first. It is such a nice little machine. Even my husband loves it.
Serita