Thanks everyone.
I was secretly hoping that the expert concensus would be that "just the horizontal lines are enough!"
I know I was dreaming!!!
I think it'll be a bunch of stop-start, backstitch, stop start, etc!
Ah! what wouldn't I do for this project now, anyway, right!?!
While it might be a little bit cumbersome under the machine, it will be an easier task than sneaking around and meeting with my husband's friends.
He has more than I had imagined!!!!
Thank you, everyone, for confirming that I do need to do vertical lines.