My husband did the prep, but I saw it when it was done. He said it was not difficult at all. He used blue painter's tape over the needle bar end. The smaller holes he sort of made little balls of tape and pushed them in (make them large enough to fit snugly). The large holes were filled with balls of paper covered with tape. Everything survived the painting process (done with compressed air sprayer). Be careful about removing paper and tape, score the paint around holes before removing.
Hope this helps. Any more questions, just ask and I will try to answer them.
Pat