One of the problems with this view is that some mutations fall into more than one category.
For instance, Ka’lol chugged a bottle of homebrew, then grew Tentacle Arms and a Beak (octopi have beaks). So, Cephalopod.
Next bottle went for feathers, etc, and he ended up going Bird, possibly thanks to the Beak. That time. 
Best advice I’d have would be to figure out what category you want, then chug about 3-4 flavored mutagens. After that, regular mutagens will probably work, unless you’re gunning for something like Spider, Lizard, or Fish–those don’t have many mutations that are unique to their category, so chances are you can’t get “stuck into” them. Regulat mutagens would take you back out inito something like Beast.
I’ve been meaning to compile a list of which mutations are over- and which are under-represented, then do a Re-Org (probably add at least two more categories*) to help things out a little.
*Thinking one “Alpha” or somesuch that focuses on making Amped-Up Humans (the stat-ups, attractiveness, fast metabolisms, disintegrating, that sort of thing) and one “Chimera” or somesuch that mashes genomes together for “optimal” performance, again with likely decay.
Dunno if the Actem Labs people would be weird/bored enough to try making an Elf mutagen… 