"While you guys are tuned in to this topic...I could use some help too. I've checked many multi-room diagrams; they don't clarify the answer, which may be obvious but it's not clear to me."
'kay
"I'm about to buy the UTV Dual (2) Sony SAT-W60 system. and so I'm planning my cable installation."
I'd consider DirecTiVo's - I've used both and I know I'd buy a DirecTiVo over the UltimateTV anyday - TiVo has a far nicer setup
" Where will I place the MultiSwitch?"
Doesn't matter much really (DirecTV only - they use tone switches - DISH switches are less reliable (but more advanced) serial switches and must be as close to the receiver as possible)
" My dish will be 25 feet from the ideal GroundBlock spot along the way into the house."
Not bad at all
"My longest cable run from dish is 25+GroundBlock+77 feet =102.
Shortest run is 25+GroundBlock+38 feet =63 ."
Both more than acceptable provided you use decent cable that can carry the voltage
"I am trying to minimize both cost and cable customizing, but if I have to cut&crimp bulk cable I could use your help to find Beige or even White RG6."
That'll be tough, but it exists. I've also seen some nice pretty blue stuff
"1] Where will I place the 2x4 MultiSwitch, at/near the dish so I have to run FOUR cables all the way to the 4 tuners? Or can I run 2 cables from the Dual-LNB to the MultiSwitch inside the house then branch out the four cables from there to the four tuners? Prettier."
I'd suggest using your multiswitch as a ground block, reducing connections (and therefore signal loss).
"2] Are MultiSwitches weatherproof, if placed at the dish?"
Yes, they are more or less waterproof.