I have not used the PMDD (poor man's dosing drop) method, but EI will work well for you.
threads are below for more info, but in summary:
We use dry powder ferts for our macros. You just mix with water and dump in the tank water. You can dose daily, 2x, or 3x per week as per your schedule. You can use MORE OR LESS than the thread recommends based on your configuration, plant mass, etc. You need to do 50% weekly water changes which will reset the nutrient level in the tank so you don't get a large accumulation of nutrients.
However, you would need to really overdose to cause issues for the plants and fish in the tank.
Here is a nice thread that speaks to EI and other methods including PMDD:
I have a 20g and a 5g. right now i'm using equilibrium and excel for ferts. I've been reading about the EI method but i just could figure out which ones i need and that is why im leaning to PMDD method.