I have done non root implementation of CMOD for the last 15 years, since it was possible to do it. And without any problems.
I would say that now in Switzerland no CMOD is using root account anymore, or at least 99.99% of all customers :-D I don't know all of them!
Now the installation with non-root, as you have found out, you cannot change the installation path. It will ALWAYS be $HOME/ibm/ondemand/Vxxxx or $HOME/IBM/ondemand/Vxxx on AIX.
Of course you can trick with the silent installation file, BUT all upgrades, etc... won't work. This is really sad and InstallShield is not really flexible in that area... I would like that IBM ditch that install software, but one can dream!
Nevertheless, what I also found is that if you install in a non standard installation path (I mean the official /opt/ibm/ondemand/Vxxx or /opt/IBM/ondemand/Vxxx), and it doesn't matter if you install with root or non-root ( $HOME/ibm/ondemand/Vxxx or $HOME/IBM/ondemand/Vxxx is NOT standard installation path for OnDemand strangely enough...), then you need to use the variables:
ARS_INSTALL_SERVER_Vxxx_DIR
ARS_INSTALL_ODWEK_Vxxx_DIR
And be careful that ARS_INSTALL_SERVER_Vxxx_DIR = ARS_INSTALL_ODWEK_Vxxx_DIR.
where xxx = 101 for OD V10.1
xxx = 95 for OD V9.5
xxx = 90 for OD V9.0
xxx = 85 for OD V8.5
Otherwise, I have found that some actions like all tools based on ODWEK (ICN) and some internal tools of CMOD, are lost in space... because for some reasons they still look at the /opt/... standard path...
Regards,
Alessandro