[name_f]Frances[/name_f] is the typical female spelling, so unless for some reason you really prefer the look of [name_u]Francis[/name_u] I think it makes more sense to go with that. Also–my grandfather’s name was [name_u]Francis[/name_u], and my cousin’s middle name is [name_f]Frances[/name_f] after him, so using the feminine spelling as an honor seems very natural and intuitive to me. [name_u]Love[/name_u] [name_f]Frances[/name_f]/[name_u]Francis[/name_u] as a name, and I’m glad to see people using it.
[name_f]Frances[/name_f]
Definitely [name_f]Frances[/name_f]. Such a gorgeous name and still a lovely way to honour your grandfather spelt this way too!