My wife also used a Terry Butterfly with a suspension seatpost and had numbness issues and soreness.
On advice I read here (or in another subforum), firmness was recommended since the softer set-ups initially start more comfortably, but tend to get wearying as the ride gets longer. After I swapped her set up with a regular seatpost and a Brooks Countess, she's had no comfort issues at all! The first time she tried it she remarked the saddle was hard. At the end of the ride (about 25 miles) she said she could have gone on longer. After the past 6 months, she's still had no issues and doesn't complain about saddle soreness. Just tired thighs.
Oh, she also tends to sit more upright and uses North Road bars. She also likes wearing knickers and has never really used bike-specific clothing. OK... she wore some one time...