I fully understand your concerns. I'm experimenting with mixing my own formulas for the very same reasons.
Originally Posted by kjsphoto
Steve Anchel's Darkroom Cookbook and Film Developing Cookbook are surely the first requisits you need. Then you need a good scale and preferably an automaric stirrer.
If you want to start experimenting with developers, I suggest you start with the D23 2-bath developers described by Steve. They are really simple to mix, give very good results, require only three relatively harmless components (5 gr metol, 100 gr Sodium sulfite, and either 15-60 gr. washingsoda or 20 mule team borax per liter). And it's really difficult to spoil your negatives in a 2-bath developer. You can't really go wrong with this. Afterwards you can try mixing more difficult stuff.