I can't answer your questions because I'm new to spinning as well. But I can comment on my personal experience with homemade drop spindle vs a purchased spindle. I started with a spindle made from a pencil, a cardboard circle for the whorl and a cup hook screwed into the eraser. It worked somewhat. The whorl wasn't heavy enough and didn't spin long. Then DH made me one from a dowel and a circle of wood cut with a hole saw (make a hole in a door for a knob) and a cup hook. This spindle worked so much better! It spun longer than the pencil but still not as long as I've seen in videos. I longed for a bought one to see what the difference was. Well, last Wednesday I ordered a Golding
spindle and received it on Thursday (that was quick!) and I will never look at Dh's spindle again. My toddler can play will it. The golding spins forever and my singles are much more consistent and thinner than I could make on the homemade one. I guess the whole point to my post is this... Even though Dh's woodworking skills just weren't good enough to make a balanced or light enough spindle for the yarn I wanted to make, his skills were good enough to see if I liked spindling before spending a lot on money on this new addictive hobby.
Just jump in a do it. You can get spindles for as little as $10-20. It is a lot of fun and you can do it anywhere. Good Luck!