Thank you! If you plan on mixing the Eros with anything it should work well, but be careful if you plan on having sections of the 2 together, and sections of just the Eros. If you just keep the same number of sts per row for the Eros sections they will pull in and narrow. What I did to keep my sides straight was to inc my first row of Eros-only (going from 18 sts to 27 by doing *k1, kfb, rep from *, and then do my 9 other rows with 27 sts for 10 rows total, and then on my first row of the upcoming Eros/Mohair section I would work the first row as *k1, k2tog, rep from * to get back to 18 and then work 4 more rows for 5 rows total.
Love your grandma's scarf. I have some eros & want to knit a scarf. I like the idea of mixing it with black mohair. Grandma looks great....