While having your high pressure storage tanks in series or parallell doesn't really matter, there are a number of ways to hook up the tanks, some of which may offer advantages. (Note that vent valves and pressure gauges need to be included, too, but aren't shown in the diagrams.)
Code:
1) Compressor------tank----tank-----regulator
2) compressor------tank-----regulator
| |
---tank---
3) compressor-----------------regulator
|
-----tank----tank
4) compressor-----------------regulator
|
|-----tank
|
|------tank
These should all work about the same, but methods #3 and #4 offer a reduced amount of tubing should your storage tanks be located somewhere other than in close proximity to the compressor and regulator. Note, of course, that longer runs do mean reduced flow... whether this is significant varies on your system's air demands and tubing lengths and diameters, of course.
You may also want to consider the potential for putting a storage tank downstream of the regulator
Code:
compressor-----tank----regulator-----(long tubing)----tank--valve---piston
|-------|
This may be useful if you need a lot of flow at the piston, but are worried about flow restrictions in the tubing. The air stored in the tank downstream of the regulator would only be at 60psi, but it would be right there, where you need it.
Keep in mind that the valves should be reasonably close to the pneumatic cylinders so that you do not have to vent the tubing as well as the cylinder when you change its position.
Jason
P.S. Hmmm... pardon the dots in the ascii "art" above... but CD seems to keep ignoring the space characters... any tips on how to keep the leading spaces without resorting to dots would be appreciated.