I hesitated, a long time, before I got into DIY. According to my records, I've mixed about 20 liters so far. When I started, without vanilla flavors I don't think I could have succeeded. Now, I can't stand confection or fruit flavors.
For sanding, I just use quality sandpaper, folded to suit, and my hand/fingers in 60-180 grit depending on what I'm doing. 60 grit for first coat of spackle and working up for finish work. In terms of getting brushed paint to have the slight "stipple" effect of rolled, good luck. A brush, when properly used, leaves a much smoother finish appearance. I use small rollers with replaceable covers, four and six inch, for smaller areas. I've gotten hooked on the plastic, throw away, roller pan liners for everything. Makes cleanup a lot easier.