Can you controll recycle stacks such as propane tanks?

Yes! That can be controlled with the Max Items Per Recycle configuration option.

Please note that the name of this config option will change in the upcoming v2.0.0 release, which is currently undergoing beta testing. Please try out the beta and provide feedback if you are interested.

https://umod.org/community/recycle-manager/44014-recycle-manager-200-beta