Most efficient (timewise) meditation techniques to experience joy and bliss? If meditation techniques were ranked by how quickly they can instill and develop the feelings of joy and bliss within oneself, which ones would be ranked at the top and why?
Joy and bliss arise when the five hindrances (desire, ill-will, sloth-and-torpor, restlessness-and-worry, and doubt) subside.

The desire for joy and bliss falls under the first hindrance. So whatever is the fastest technique to make you forget that you're seeking bliss... that's the fastest technique for seeking bliss :)

Subduing the five hindrances is the "first stop" for all meditation techniques, whether it is breath-counting, breath-following, metta, noting, or devotional practices. Different people respond in different ways to each of these. So try them all out and see which one motivates you to stick with it- that will be the best.

Two warnings:

(1) Joy and bliss are conditioned states, so they can disappear as quickly as they arise, especially early in your practice (and "early" may mean years). If joy / bliss fades, or doesn't last past the sitting time, it isn't a failure. It's the natural passing away of all conditioned states.

(2) Not everybody experiences joy and bliss when the hindrances subside. Some people, particularly those with a trauma history (though nobody knows for certain why), may experience disturbing imagery or emotions. If this happens, be careful about pushing your technique too hard. Some Buddhists will insist that it is a sign that you are not meditating hard enough. Be wary of this kind of advice. Not all problems are solved by meditation, and other kinds of work may be necessary too.