RDWC is my favorite way to grow. I've done a shitload of crops using that method so i think i can speak on this with absolute confidence.
5.8 to 6.2 pH is good. When i veg i veg with a 5.8 pH. When I flower i raise to 6.2 because the macro elements are more available at that range for flowering, namely P and K.
You can't go wrong with following the feed charts recommendations. The strength you feed will be up to your plants and you to experiment with. Light feed will be fine and the safest method of feeding. Heavy feed not every plant will be able to tolerate. If you want to try it i suggest you ramp up each week instead of just blasting them all of a sudden.
I have a bunch of GH stuff but right now i'm enjoying Remo nutrients because it's just really simple to use and seems to be working out really well.
The biggest worry i would say about RDWC is your reservoir getting depleted of water as the plants transpire and the water evaporates. That is a problem you have to be most careful of because the water will go and the nutrients will become more and more concentrated and eventually cook your plants. The best solution is to install a float valve in your reservoir and have a 5 gallon bucket with more nutrients mixed up and hook it to the float valve so when the water level drops the float will open and the res will get topped up by the 5 gallon water reserve. ;)
I have a discord if you would like to join where we talk about all things growing, including deficiencies, techniques, you name it. You are welcome to join. Just DM me and i will give you an invite link.