OL silver vs. Clearaudio Unify

Here my ignorance shows: can an arm's effective mass be enhanced by adding weight at key points on the arm and/or headshell? (and therefore work with lower compliance cartridges?)

Thanks for all your responses. As to why I am leaning toward the Unify - it is quite simple, I have found one which may come in a bit cheaper than the OL Silver. Also, I am not crazy about the plastic base of the Silver (i.e. I find the esthetics of the Unify more pleasing [a lame concern, I know]). After your input, I may be pursuing the Silver instead. . .

Thanks again,
Joel