Thanks so much for your reply. Yes, I have two ratchet blocks ready to go - I completely agree with what you said and the picture you included is exactly what I purchased.
My reason for the winches was because I frequently single hand and the only winches on the boat are the primaries on the cabin top. Adding some winches a little more aft would be more of a convenience thing. You might be right, though. Might be better to save the money. Thanks again.
In this case it might be wise to consider upgrading and relocation your primaries to a location closer to the helm. You can always use the cabin mounted winches if you need help with the spin sheets. What you'll find when working the spinnaker is that the trimmer will likely prefer a windward position (often standing ahead of the helm on the side deck) so the chute's luff can be observed.
On my 27 footer, I have a pair of small, single speed, standard Lewmar 7's aft of the primaries put there by a previous owner, theoretically, for spinnaker work. Even though that seems to be the obvious designed location for these secondaries, the real world use of the spinnaker has taught me that the trimmer is NOT going to sit back there, on the leeward, aft corner of the cockpit. No room, no visibility, and really no necessity to winch the sheets anyway.
What works best is to route the sheet up to a cabin top winch and reach across to the windward, forward side of the cockpit. Putting in new, closer to the helm, primaries will handle the heavier chores, freeing up those more forward winches for the cross-sheeting arrangement. The other crew can then tend the guys, mainsheet/traveler and other controls as needed, yet still be in position to help the spin trimmer. So, with that in mind, now might be the time to pull the trigger on some new bad ass winches that'll give your boat some real options for more efficient sail handling. Good Luck, Have Fun