CN built about 30 345s, after which they sold the molds and tooling to a Fast Yachts in Brazil, who went on to built approx 130 of them into the 1990s. Like so many builders this company is now defunct (and unrelated to the Fast Yachts in South Africa, AFAIK
Fast 'crusified' the 345 considerably, replacing the forward pipe berth/sail area with a standard V berth, and converting the salon pilot berths P&S to large storage cabinets. The layouts, and the storage locker arrangements evolved throughout the production run with a number of variations. Probably the most significant change was made at some point when they went to a masthead rig.
We own Fast 345 Hull#41, with the standard (original) fractional rig. 3/4 at best, she's a little underpowered in the real light stuff. but comes into her own nicely on the beat at 6-8 knots true (that's without a genoa, just a working jib - btw a J 105 mainsail fits nicely
She has a large rudder, and while there's no doubt the IOR 'shape' to the underbody, I think the smaller foretriangle of the frac rig mitigates a lot of the issues with this era of boat. We have owned and sailed other IOR beasts with all their propensity for death rolls DDW.. in 8 years we've yet to experience this with the 345. Since the headsails are relatively small we fly the spinnaker routinely while cruising.
The biggest 'surprise' on these boats (esp for what is essentially a late 70s design) is the totally usable aft cabin double - and this in a skinny a$$ed IOR boat with somewhat pinched ends. Good aft cabins are de riguer today, but they were near unheard of back then. I suspect that the interior is primarily CN's work, Holland probably provided hull and rig designs primarily, but I'm not sure about that. There is a large bridge deck that facilitates access and headroom in the aft cabin, and it does cut into cockpit seating somewhat, but at rest it's also a great lounging area and for two people the cockpit is adequate.
Another unique feature is the 'trunk'.. these boats came with a removable transom section that enclosed a liferaft cannister storage compartment. We use it for storing extra fuel, and when we're between garbage dropoffs we put that back there.. with a little ingenuity and glass work one could create a stern platform there to update the boat a bit.. but the ladder is a good one, deep and sturdy, and we've chosen not to mess with that.
So as someone familiar and accustomed to IOR boats and their foibles, this one is a mild version... whether the 303 or 33 would behave similarly I can't say.