The centre nacelle does reduce the impact of slamming, but not all of the noise
, but slamming is only a feature of working to windward or against swell and current
Running on a broad reach it's rarely any issue at all.
The bigger Prouts, 37ft plus, are excellent boats, not the fastest but then you are cruising.
I've seen an old genuine UK built Prout 37 at under 100k recently. For a beginner I'd recommend you learn on something that won't depreciate so quickly for a few years.