What alternatives do you recommend when you make mistakes starting sculpting with dense polys?

First of all, thank you so much for such an excellent course!
It helped me to understand the basic concepts behind sculpting, understand flows and the general tooling available in blender.

Unfortunately, I started a project before signing up to this course and immediately run into some issues and making wrong decisions which I was expecting it, that's the learning path. :) So, to get to the question, here is the link to the project I was talking about: https://cgcookie.com/u/kuakman/projects/human-anatomy.

Seems like I made a mistake, starting with a high dense polygons in the areas of the feet and hands.
The flow I picked to start was the multi-res modifier and I put a lot of work in other areas such us, the body.

What are my possible solutions to retain (or preserve) the details I made in the areas of the body but, removing at the level 1 some "geometry" in the areas of the hands? or simplifying it (less poly count).

Also, You will see in the project link, a youtube video of me sculpting a hand. That hand was created with a different topology (simplistic) just as a test, to see how it feels, and seems to be working better. But unfortunately that one is not part of the other model. I noticed that I was spending too much time with the high poly count version, the mesh doesn't seems to work by inflating, flattening. I tried using the move tool but something doesn't feel right, I keep working on and on... but the mesh doesn't get to the way how I want it. In the other hand, I know hands and feet are a complex part of the human anatomy.
So, here is the link to the low poly count version of that hand: https://www.youtube.com/watch?v=ui-AkzFLCKQ

Would you recommend instead using the Skin modifier, build super simple and independent objects and sculpt one at time and then use something like Sculpt Tools to merge them together via boolean operations?

Thank you so much for your time!