I use 30-40% perlite TOTAL depending on what I need it for. A sick plant suffering from sodden soil and root rot gets repotted into the lighter mix obviously. I've gone up to 50% in extreme cases but that's not really a medium to grow normally in.

Your mix already has a bit in it so yeah, I'd add up to about 20-25% more, if even that.

Light soil is great but remember to keep on top of watering.
stinkyattic Reviewed by stinkyattic on . My soil good to use? IN CALIFORNIA AND GEORGIA, THIS MIX CONTAINS 68%-72% SPHAGNUM PEAT MOSS, VERMUCULITE, AND PERLITE AND LESS THAN 1% FERTILIZER AND LIME FOR PH BALANCE GUARANTEDD ANALYSIS Total Nitrogen (N) 0.09% 0.04% Ammonical 0.05% Water insoluble Available Phosphate (P2 O5) 0.05% Soluble Potash (K2 O) 0.09% F-1431 :dance::gunfighter2::chainsaw: Rating: 5