The smaller the instrument the more sting. The larger the instrument the more thud as a general rule.
The harder the toy the more thud, and the more flexible it will whip more and sting too.
To be quite honest I think paddles are fun, but if you want some versatility buy household items too. A wooden spoon works great. A small cutting board works great. There is really no toy that is going to provide a large variety of sensations. Because you cannot have a large and small flexible but hard toy.
Most toys though can simply be used lightly. I would suggest a suede flogger for a whip. It can be light, but swing it hard and it hurts. For a paddle I would suggest something medium sized. You can swing it lightly, or hard. And again I would try a wooden spoon too.
Also go to your local tack shop. You can pick up a riding crop for like 3 dollars instead of paying like 20 online for a BDSM crop. The local tack shop will also have a nice one too probably.