In general we follow Jeff Hunter .
However, scripts starting ASM databases are not
quite like as in  due to different ORACLE_HOME's directories for ASM instance and database utilizing ASM in case of 10g R2 version of server. In 10.2.0.1 case script /etc/init.d/dbora doesn't export any ORACLE_HOME value.
It just runs script in ~oracle directory responsible for export right ORACLE_HOME value at right time