WHAT IS THE BEST TIME FOR MS OPERATION?
In the morning hours, around 0600 local time, that part of the earth is facing the same direction as the direction of travel of the earth in its orbit around the sun.  Thus, not only are meteors swept up which are
heading toward the earth, but the movement of the earth around the sun allows it to catch up with some of the slower meteors and pull them in, also.
     On the evening side (facing away from the direction of the earth's orbit), the only meteors reaching the earth are those which can overtake it.
     The best time for visual observing is considered to be between 2 and 4 am local time. This is because during the season when the sporadics are at their peak (summer), the sky brightness is increasing after 4 am.
     It must be remembered, however, that many or probably most "sporadic" meteors are actually the remains of long-gone showers.  Thus, on a given day, there could be meteors 5 or 6 of these "extinct" showers hitting the atmosphere, causing an enhancement at an unexpected time.
     There is a considerable seasonal variation of sporadics, also, with February being the low month and July being the highest.  (KB0VUK has graphs of this on his Web page, I believe).  Take a look at the number of major and minor showers in the June-September period and the reason for this will be obvious.
     There are also several other factors that influence the number of sporadics, and also the ratio of morning to evening.  But these are not that important.
     The best reference for MS operation is still the second article by W4LTU, reprinted in "Beyond Line of Sight" (ARRL).  This is NECESSARY reading for anyone thinking of MS operation.
     Yes, HSCW is possible any time.  But there are 4 to 6 times the average number of sporadics at 6 a.m. local time than at 6 p.m.   But on a good path, evening operation is quite possible.  (On a difficult path, unless there's a shower peak, I wouldn't try evenings.  Just not enough sporadics).