Such a good scene, very immersiv and with a great progression in the sexual tension.
Those 10mins~ roleplayed situation are the best scene in VAM, they are the whole point of the experience.
By using Ashley from Resident Evil after she is being possesed by the reverend Saddler, the sene can totaly be a Resident Evil 4 fanfic :p
For now, I'm leaving the plugin as it is.
Your request would probably be very difficult, if not impossible, to implement reliably.
Manual adjustments for people with different sizes will most likely be unavoidable.