Sell the kit, its **** for racing.
As for rings - dont bother, cos they wont make any difference unless you're burning oil, as its the pistons that wear and cause the slap - get better earplugs, cos slappy engines are faster.
If it blows up, I've got a spare full bottom end and a full spare engine
The problem with the valve timing is that lack of quality control on the pulleys meant that they can be at different timing on each cylinder !
That definitely loses power.
To get best performance on almost all older ducati engines it is best to advance the inlet cam timing by about 3 degrees from the factory spec - they decided on it in about 1989 and didnt look at it again until about 2002
But ! If you do that it is also best to get your squish set up cos that also varies as standard, and you again lose power if the two cylinders are different
Starts to add up doesnt it
If you're not at the front, just work on your cornerspeed, and you'll get much better value for money