For me it really depends on the specific names. I like alliteration generally, but double letter alliteration might be more likely to tip over into too matchy or cartoonish. [name_m]Not[/name_m] a definite thing though! Plus sometimes the sounds are actually a little different – I’m thinking of the singer [name_f]Charlotte[/name_f] [name_m]Church[/name_m] for example. That would be less risky IMO.