I would suggest using the Necchi if it has a center needle position. There are not any ruler feet available for the slant shank machines so far as I know. I do a lot of ruler work on my domestic machines and love doing it. The Westalee ruler kit that includes the ruler foot and a selection of rulers is a good deal if you want all the rulers that are included with it. I find that I tend to use my straight, circle and arc rulers more than anything, though I do have a fairly large selection of other rulers for doing specific things, like Baptist Fans, clamshells, snowflakes, curlycues etc.
I really enjoy using the rulers, and I often combine ruler work and regular FMQ in my quilts--it's a lot of fun.
Rob