Yes it is okay to just use RF, I do it all the time.
Now that you are set at 70 it sounds like the hairs are releasing properly.
The little white dots you have after can either be overtreatment, if the areas surrounding the follicle is white after treatment, but if it's just inside the follicle you need to gently remove that with your tweezer, it's just dead cells that got stuck coming out with the hair and bulb etc.
As for your DC questions, I would suggest you try a five second timing to start since you are a beginner.
So figure out an RF setting for 5 seconds of timing and then do the math to figure out the DC.
45 units of lye divided by 5 seconds = 0.9 mA
Send a private message if you don't understand okay?