Firstly, you don't necessarily need hair to hide the lace. The lace blends with the skin, so even if there isn't hair, you won't see it.
Secondly, there will be hair, so its even less of a problem!

Places like TopLace make fake eyebrows & moustaches which are small sized pieces.
As they say, size doesn't matter!

A small front partial won't show any more or less lace that a normal size hair piece.