Maybe this is why I find I brew them inconsistently. I take my coffee game very seriously, but I've never bothered to weigh tea. Maybe I should.
I learned another method for oolong tea from some Chinese coworkers called grandpa style. You leave a few oolong leaves in the bottom of your cup and just continuously top it off with hot water.
(One aspect their site is weak on is customer reviews. You can't review unless you order more than a sampler and they archive reviews regularly, so I keep mine on my own web page: http://www.gwern.net/Tea )
I don't think a gram scale is all that necessary since you can easily calibrate the amount to your liking, and I've gotten by fine without using one for years. It is helpful for side by side reviews so you can be sure you are comparing different teas favorably.
I could get by without using a gram scale, but mostly I like having it around for peace of mind. I didn't figure out the right tea/water ratio for my oolongs until I started measuring them. It's also nice for when you have a particularly expensive or rare tea and you want to make sure that everything is perfect.
"Get the leaves wet and drink the water" is really all you have to do for tea. All these other rules are just people saying how they like to have it, but you don't have to.
And yeah, oolong variety is not as well-known as it should be. Blame it on health-hype for green tea.
San Francisco's Song Tea is expensive but superb — try the Shan Lin Xi Winter Sprout for one of the best teas I've ever tasted. (And don't knock over any of the $200 teapots!!) Red Blossom is great as well. You can smell all the teas before you buy — and they all smell surprisingly different.
Oolongs are best brewed using a lidded cup (gaiwan) or small teapot, but it doesn't have to be anything fancy. I actually use an insulated stainless steel mug[1] that does the job better than my old porcelain gaiwan. A gram scale is highly recommended for getting the proportions right; a teaspoon can mean something completely different depending on whether your leaves are rolled into tight balls, loosely packed, etc. Loose-leaf oolongs are generally brewed a bit differently from black teas: instead of steeping a small amount (2-3g/8oz) once for a long time (3-5m), you steep a large amount (8g-12g/8oz) for a short period of time (1m or even less) and then resteep multiple times (3-5 or even more). I used to use a thermometer to get the temperature right, but it honestly doesn't matter: most oolongs brew at boiling or close enough to it.
[1]: http://beta-blog.archagon.net/2015/12/26/the-perfect-travel-...