Red-eyed v Small Red-eyed
Red-eyed tend to come out in May and peak later May early June, small red-eyed tend to be more of a summer species peaking July.  Saying that they definitely is cross over when they are around
Males: small red-eyed tend to have brighter red eyes, but sometime hard to compare as depends on lighting condition, age etc.  The best thing I use for comparing them is that the blue at the front and the rear of the small red-eyed abdomen goes slightly further to the centre than in the red-eye
Females, the shoulder strip is complete in the small red-eyed and incomplete in the red-eyed