It will make life much easier for you if you use a stereo delay with panning, rather than trying to use two separate delays and setting them separately (note that they're not set at the SAME rate- one should be set to twice the delay time as the other, (say, 500 and 1000 milliseconds) so you hear the same thing three times at regular intervals).
Yes, the latter method is the way Brian May did it in the 70s, but if he had the option of doing it with a small, reliable digital delay that did all the work for him rather than two bulky, temperamental tape echo units that had to be dialled in to get the correct sound, he would have done that instead.
Most stereo delays will pan repeats left and right automatically, and the repeats will automatically come back equally spaced- use two separate delays and you'll have to tweak them to get this- and in many cases can be set by tap tempo so that you don't have to dial in the right tempo for the song, then rely on your drummer to play at the same speed every time!
Brian's setup used three amps (or three SETS of amps!) for dry signal, left and right echo repeats. You can get away with two amps, as the dry signal from the delay will normally be output through both amps.