Hardware for poudriere

I considered running a local poudriere for arm64.
I have no experience with poudriere so far, just know that compiling
ports nowadays is a matter of RAM and lots of patience.
However, most of my systems only have up to 2GB RAM.
The exceptions are 4G Rockpro64, of which I have 2 unused.
And a Pi4 with 8GB.
I personally prefer the RockPro64, because it is the better hardware.
But the Raspberry has more RAM.
Would 4GB be enough.
Can multiple host be even clustered for poudriere?

-- 
B.Walter <bernd@bwct.de> https://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.