Welcome Jan.
I'm not sure about ruler work on the 99 as the feed dogs don't drop. There was a feed dog cover plate that could be used for darning and embroidery, but it did not come with the standard attachments. The machine needed to be threaded a tad differently than regular sewing.
Do you have a manual for your machine? You can see some ruler work Theresa has done with a 15-88 at
Ruler work on my 15-88
Glad you know that the red felt is supposed to be there. Yes it can be replaced. I would suggest you download all the pdf files at
http://web.archive.org/web/201610160...achine_manual/ They are for non electric machines (15, 66, 99 & 201), but an
excellent resource. "The lower bobbin area" pdf has how to change the felt on page 3.
Have fun.
Janey - Neat people never make the exciting discoveries I do.