Hi
I assume you are referring to the plastic shocks....
350 - 450 cSt oil is typical for carpet.
The new shallow shock membranes (308081) work well and are easy to bleed
I tend to run low/no rebound on carpet, 50% rebound on asphalt
I have drilled the shock top with a 1mm hole into the bladder cavity to reduce rebound
My method to bleed and set rebound on plastic shocks is as follows:
1. Fill with oil to the top
2. SLOWLY pump the piston to get the air bubbles out from under the piston
3. Slide the membrane onto the oil surface, and hold with your finger
4. Carefully slide a small cable tie end (or screwdriver blade) between the membrane and the shock body. This will release excess oil from the shock body
5. Fit the shock top and cap
6. Check the rebound (often this will be correct already)
7. If not, extend the shock fully, and hold upside down, loosen the bottom cap
8. Firmly "tap" the end of the shock shaft with your finger a few times. DO NOT pump or pull on the shaft as it will pull air into the shock body.
[You are trying to squeeze the (thick) shock oil out of quite small clearances between shaft and body, a slow push just deforms the membrane at the top, and does not create enough pressure inside to force the fluid out of the bottom. A "pull" on the shaft creates a partial vacuum inside the shock, and (thin) air can get in really easily]
9. Recheck rebound
10. Repeat 7-9 as necessary - only a few repeat cycles are needed (2-3)
Hope this helps