I wouldn't advise soloing for seals over going with a standard WHM/RDM, BLM/BRD, BLU, and NIN or THF tank setup. In an hour of shouting (hopefully less), and an hour of killing, you should get half your seals for a head/leg/foot piece, more if luck be a lady. Make it an hour and a half to two hours of NM killing, and you'll be done before you know what hit ya.
Hands and body will be harder because they're in Heroes areas thus higher level, are a bit more expensive to pop, and in my personal experience, harder to get ppl for. No idea why, they're newer so people should actually be more likely to need them...
There are two kinds of people in FFXI, those doing the laughing and those who don't know what's funny.