Enjoying X100 a lot, but wish I could get a better grip

I have reasonably large hands (for a bloke), and my only gripe with the X100 is the lack of grip in its 'naked' state.

I've been looking at the Really Right Stuff l-plate and grip, and the thumbs-up thumb rest as options. They are rather expensive, and without a local shop where I can try them out, I really am relying on other user's views on these.

Are they worth it?
Do they just get in the way of an otherwise tidy package?
Do they make a signifcant difference to handling?

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Kind Regards,
Rich
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