I do not know how many, if any of you use this, but I have found that the more highlighting I do the more I like to use a wet palette. Here is an easy to follow article about building your own. I actually do not use the wax baking paper, I purchased actual wet palette paper, but I may use a few sheets of it between my paper and the sponge. Otherwise I did exactly what is done in the article.
Using a wet palette has really helped me with my crude highlighting and limited time. I can make my highlight shade, do one model, then come back later( usually the next day ) and begin another model and still get the same shade.
As far as inks go, I have come to really like the GW brown( which they no longer make) and tried many different things over the past year without much success. Now comes this. If only this was written a year ago. I tried this recipe, using liquitex inks, and have been pleased with the results. Now I have a big bottle of black ink and a big bottle of sepia ink. I wonder how long it will take me to get through them? FWIW you can buy liquid ink in smaller sizes but they do not come with droppers.