Looks like Lakewood or GK could have some input too. This is how I am approaching my add backs. Tell me if my Mode of Operation is flawed?

I set up my resi and wait for water to go down. I add back with full strength solution. I am changing out my resi every 2 weeks. I have been instructed by the person selling me the nutes to replace the solution weekly but in an effort to save time and dough I am experimenting with twice a month.
I am set to do my first resi change in the flowering period tomorrow. Things seem to be ok. I noticed a bit of what I reckognized as a mag deficiency so I did toss in some extra cal-mag at 10 days.
I noticed that in the lucas method it is suggested to let the resi go until PPMs are raising too high.
I don't like this thought because I know that some nutes will be used more than others and the balance will be thrown off more and more.
I guess the threshold of ppms lined out will keep the solution from becoming toxic but I am afraid to run an experiment and have my grow get jacked.
Anyone out there using a full strength add back routine? I would love to hear a voice of experience.

Thanks guys, -Jay