[jhautz]

Packing the tranny with grease will do 2 things.... Add rotational resistance (just like packing a diff with grease or silicon fluid) and add useless weight. (And quite a bit)

Graphite power should be just fine. I have also had good luck with the dry silicon lube they sell in bicycle shops for chain and gear lubrication. (goes on wet but drys quickly to leave a silicon deposit.) Prevents things from sticking in the lube and doesn't fly off in high rpm.