Of course personal taste!
I would agree that weight distribution is critical, but the most common complaint with sports like silhouette is that the rifles are too light. David Tubb went on at length about this in his second book, as well as Maik Eckhardt in his book, Ways of the Rifle.
If you look at the rifles used in olympic events, they are much heavier that we expect, and use the heavy single shot actions. The large heavy action creates a much better ballance point because of the large barrels and extension tubes used. There is an outstanding discussion about this in The Ways of the Rifle.
For modular, again G&E, Walther, Anschutz, Steyr, ect sort use the same flavor of stocks, but the G&E is so much more refined. I like the G&E with MEC parts, they just seem to go hand in hand. But there is no doubt that many of these rifles are setup to add weight in various locations rather than loose weight. I'm still trying to figure out all the possible places to add weight on my 9003 air rifle. I'm not real familar with any Italian olympic rifle, but I sure love their pistols.
For prone, wood stocks are back in favor, due to their harmonic dampening, and if bedded correctly, they are just as stable as any alu stock. Eric Uptagraft has moved back to the wood stock, but I'm not sure what Matt is shooting - aside from the heavy Anschutz 2013 action and Lilja barrel combo. Both Matt and Eric favor heavy rifles for off hand. Their prone guns are tanks.
I think silhouette is so difficult because of the weight limits and stock restrictions. With reverse taper barrels and counter-bored muzzles, a silhouette rifle can really be comfortable. "Pointability" changes quickly over the duration of a match, and the rifle's CG will become critical as the day wears on, and having weight close to the body's center is very important. Staying within the 10.2 lbs is just maddening when a 14lb rifle seems just right.
As for scope, when I can figure out how to make weight with a Nightforce, I'll be happy, but i ain't giving up the 54 action!
Now, what you come up with for the 10/22 is gonna be pretty interesting, and i'm curious as to what direction you are gonna go. Any hints?