Not trying to make this more of a debate than it needs to be, but two things still escape me:
1) if you still only install one restrictor at the valve but install it on the down line (return/exhaust side of the up circuit), you would still get the full volume of air to the cylinders on gear up just the same as you would if each cylinder had it's own restrictor on the exhaust side of it, right?
2) no matter what, and assuming a successful flight, each line is an "exhaust" line exactly half of the time. So if the retracts need volume and that's why you put the restrictor on the exhaust side, then when you flip the switch the other way aren't you fighting the exact battle you just mitigated by restricting the volume for the reverse operation? So your gear might come up nice and slow and smooth, but then will they struggle to come down because you've now restricted the volume on that side of the cylinder?
Again I'm not claiming to know any better, just trying to understand a little more. Probably just overcomplicating it, I tend to do that. I know lots of pilots have had lots of success and I need to just start hacking open lines and experimenting (boy I wish I had festo push connects throughout my planes instead of barbed connectors).