best practise for eclipse launch arguments

-vmargs
-Dosgi.requiredJavaVersion=1.5
-Dsun.net.client.defaultReadTimeout=3000000
-Xms128M
-Xmx512M
-XX:PermSize=128M
-XX:MaxPermSize=256M
-XX:+UseParallelGC
-Dorg.eclipse.ecf.provider.filetransfer.excludeContributors=org.eclipse.ecf.provider.filetransfer.httpclient
-Dhttp.proxyPort=8085
-Dhttp.proxyHost=xxx.com
-Dhttp.nonProxyHosts=localhost|127.0.0.1