You might give an antispasmodic, antiepileptic drug a try. Klonopin is a benzodiazepine with more antiseizure properties than other benzos (you said that you tried Ativan, but that's more of an antianxiety benzo). An anticholinergic such as Artane has helped many tremor dominant PWP, so has the cardiac medication Inderal, Requip, Idunno, my experiences were horible with it, but many others have had good luck with it. Methocarbamol and Flexeril are both muscle relaxants (flexeril is interesting because it bears a very similar molecular structure to the so called "tricyclic antidepressants" such as Amitryptiline. Most neuros precribe the metabolite Nortryptiline, as a way of an attempt to control tremors in PWP by controlling or combatting depression, and as a sleep aid. I tried it but it, but it didn't do much for me). Neurontin coulld be another drug to try, i use it occasionally to combat tremors, but i am not a tremor dominant and only get the bad tremors when i am like totaly stressed out, but if i get that bad, i usually just go to bed, a luxury that I only got since i "retired", and one that i know what it feels like in the workaday world all too well. I use Amantadine regularly. I find it an " neccesssary addition to my sinemet"; for some reason the sinemet just isn't as effective without the Amantadine. I've mentioned in the past that alcohol is effective in controlling tremors, but this is a difficut drug to use, as addiction and other issues rear their ugly head all too often, and one certainly can't be drunk at work, and one also risks "falls" with alcohol use. Some people use the antihistamine Benadryl with some effect on trmors.
You have posed a difficult question, without any one good answer. It's going to be a "trial and error" thing. A lot of good advice has been given and i would tend to say that when you get bad enough, even though you have to accept maybe a drastic cut in lifestyle, quitting work is one of the best ways to cobat tremors.