i have an MC8900. i believe our two machines are similar enough for you to try what i do.
when I use the free-motion foot with the interchangeable attachments, i use the open toe.
using the screw on the side of the foot assembly, i lower the toe attachment as far down as it will go.
i can use any weight thread i want in the top (adjusting needle size accordingly. i don't recall getting away with anything less than an 11. usually either a 12 or a 14. every so often i have to go all the way up to 16).
i use 60wt or less in the bobbin.
i set the top tension to the tightest setting. (that's a 9 on mine if i remember correctly. it's put away right now.)
and ... yes ... don't forget to lower the feed dogs.
when i do all these things together i almost never get either pin-dots or eyelashes on the back - even if the colors are different on top and bottom.
__________________
- necessity is the mother of invention. lazy is the crazy aunt.
