Efficiency is whorr-its about mate so running this at 28w per , works out well for me and, if I changed Driver (in future)to run at between 35/50 watts per cob, that would mstill have a relatively long life and by the time I have used them for a while, I'm sure the new next best lighting will be out etc..
so if I ran them hard at 50w per , would thet significantly lessen lights life.?
The lights Looks good mate and just in time for summer time bud..
Talk again tomorrow and you have a good night mate..
Happy growing ,