Here at NSLS2 I believe we use the following scripts to pre-load the correct PV prefix for the CA and PVA viewers respectively - the scripts are called from a button on our screens with the PV prefix as an argument:
[jwlodek@xf06bm-ws3 /]$ more /opt/css/opi/production/cs-studio-xf/ADet/nsls2edits/ImageJ_macros/css_imagej.sh
export EPICS_CA_MAX_ARRAY_BYTES=6000000
cd ~
rm EPICS_AD_Viewer.properties
echo "PVPrefix=$1" > EPICS_AD_Viewer.properties
imagej -m ~/.imagej/macros/CSS_epics.ijm
[jwlodek@xf06bm-ws3 /]$ more /opt/css/opi/production/cs-studio-xf/ADet/nsls2edits/ImageJ_macros/css_imagej_pva.sh
cd ~
rm EPICS_NTNDA_Viewer.properties
echo "channelName=$1" > EPICS_NTNDA_Viewer.properties
imagej -m ~/.imagej/macros/CSS_epics_pva.ijm