With externally adjustable Konis the best set up method is to find a speed hump in a street ...should not be too hard these days
and with the settings set to soft, drive over the speed hump at normal speed hump speed and see if the suspension bounces after you have just gone over the speed hump. If the front bounces then adjust...and retry.
You can do the 1/4 or 1/2 or even 1 turn at this stage depending on whether the car bounces a lot or little. Adjust until the front just travels over the speed hump with out any bounce. Then adjust the rears. More often or not the rears will be set to soft but you may have to adjust. The reason the fronts will often need adjusting from new is that they are usually made for a car with no allowance for rengine weight. The soft setting should suit the lightest engine.
Now with the best ride/handling compromise setting determined you may wish to go for slighly sportier if you like. However the ride will dertiorate quickely if harder damper settings used.
NB Konis are really only adjustable for wear.... If you want truely adjustable ones then something like Spax adjustables is the way to go...unfortunaltely not for modern Alfa Romeos. Spax can be softened or stiffened from a cental setting depending on the road surface and the type of driving you do. I have used them on "classic" Alfa Romeos and prefer them to Koni.