Hey, yeah I learned how to dry brush many years ago when I was working in the spa industry. I would say I do it now about every 4-5 days (that is what I aim for) or when my limbs feel sluggish. I tend to get edema in my lower body and more on one side. It is a good idea to follow the meridian lines of your body & move the brush towards the direction of your heart. These are the basic guidelines. Of course, you can always just brush anyway you like for the exfoliating benefit, but for circulation, lymph movement etc. benefits, it's a good idea to follow your lymphatic "paths". Give good attention to the clavicle area. The time NOT to dry brush or any direct lymphatic stimulation (body rolling etc.) is when you have the flu or are sick.
Any brush that you find a little firm but comfortable I think ought to work. If you have stronger/thicker skin, you could try something a little rougher perhaps. I know some people who enjoy the firmer coconut ones, but I prefer those just for my feet! I just have a cheapish one that I knew didn't use animals (boar, horse) which I bought at Winners (in USA TJ Maxx) which works nicely. Bürstenhaus is a premium brand that many spas use, if that's your style.
I also started doing gua sha/scraping the past couple of years which is the same basic idea. For me, the benefits are stronger.
Please post how you get on with it!!