More Gearing 14,15 rear?

Hi Folks, I have been watching the 14 tooth counter shaft sprocket thread and have a few questions;

Those of you using the 14s, would you change to a 2 or 3 tooth bigger rear when the chain is wore out? On my SS the 14 was ok but 2 up on the rear provided just a LITTLE less change (3 would have been the same) and that was the sweet spot for that bike. The 15 front likely will extend the ultimate life of the chain/sprocket combination.

What about ST2 vs ST 4 choices?

Reason for my questions is that we will be stocking these parts and i am looking for the best combinations to offer.

Thanks in advance for any help!

When I wear the chain out I would do 14 again and up 2-3 on the rear.
Overall the bike makes a lot more HP (see various posts with HP & torque curves) than it performs in terms of acceleration. Ducati gears them high to get past the sound tests and I believe that doing 14T and +2-3T rear is the best match for the overall performance characteristics of the engine.
Much crisper acceleration off almost any corner (like a sport bike), much more efficient use of the powerband (sport and touring)and enhances the use of all six gears (especially helpful for top gear roll ons in touring).

Also, with as easy as the 14T comes off and on the bike compared to the 15T and the fact the ST4 can't effectively use 6th gear with stock sprocket gearing under 80+ mph makes me believe that somewhere in Bologna there is a guy that engineered this thing for a 14T CS and +2-4 T on the back.
I hear you though on the chain deflection angle as a consideration for making the equivalent change to gearing thru 3T+ in the back - that's a good point - but just eyeballing the angle compared to most sport bikes convinces me that deflection is way below normal because of post-design changes undertaken for regulatory compliance (i.e., the US government agencies such as the EPA).

Uh, stupid follow-up question; Can we use the same chain length for 14 CS & + 2 or 3 on the rear, or is a longer chain recommended? I'll be coming up on this change in a few weeks.

I think that as you get smaller on the countershaft sprocket you increase the loading on the chain and sprocket teeth by an appreciable amount. 14 teeth is a common selection and not a big issue but going to 13 and certainly to 12 teeth would be noticeable. There are only about 7 teeth engaging so reducing that engagement by a full tooth is a significant thing. All the hp goes through those 6-7 teeth and chain rollers. A 45 steel rear is about the biggest I can get. And running a 14/45 as opposed to the 15/42 should only need about 1 extra link in the chain, I would make sure I had 2 extra if I was getting a new chain.

You should need one link more on your chain for each tooth you add on the rear less one link if you go down one tooth on the front.
If you convert to a different size chain it's the same principle and you may need different sprockets to match the chain size depending on what you switch to. I heat that many Duc owners convert to a more common and less expensive size chain.
You are better off keeping a continuous chain too. Most chain companies keep conversion guides that will provide the chain length for the number of teet you have on both sprockets. Most sprocket companies will tell you what size chains (530, 520, etc.) work with their sprockets.