Worthwhile Modification
I did this retro-fit on my 2004 Hunter 33 and it was pretty straight-forward.I installed two Lewmar ST30 (Chrome) winches purchased new from www.catalinadirect.com. Could not find them cheaper elsewhere. I think they were about $550 each just about a year ago. Location for the winches should already in place and you should find aluminum backing plates in place for winches to bolt through. There were on the H33. Access to screw the lock-nuts to the bolts (from below) was not too bad either. Cockpit configuration on the 356 may differ so I suggest you check first on your proposed purchase.If your two existing tracks are on the cabin top as on the H33 (ie the H33 without the genoa winch option), suggest you acquire two additional track sets for the deck. You may also have to acquire two genoa foot blocks - suggest you get the blocks from Hunter but the tracks and stoppers are not difficult to obtain elsewhere. Actually, I think you can go to the Lewmar website and they will give you all the equipment and part numbers used by entering your boat model number. If not call them, Lewmar folk are very helpful on the phone.I estimate the total cost was no more than around $1300. However it makes sheet handling a lot less cumbersome by avoiding the overcrowded cabin top. I recommend that modification without reservation. My wife was sceptical about the expenditure but now feels it was more than worth it. Good luck