Hi,
What a strange idea to put reverbs in series… Do you mean parallels ? Eventide reverbs are already so deep and “powerful”…
About the number of DSP, IMveryHO :
DSP7000 : 1 DSP
DSP7500 : 1 DSP
Eclipse : 2 DSP
Orville : 2 DSP
H8000 : 2 DSP
H9000 : much more 😉 (I dunno this rack)
Other specs can other be also interesting like numbers of (digital and analog) I/O more than the number of DSPs.
These are my 2 cents, cause I am pretty new to those Eventide “magic boxes”.