I've just put my glasses on, and yes, there are sharpening halos. Note to self - swallow pride and wear glasses.
I have worn them for decades (since I was 12) so I am actually at the point where if I had the laser surgery and it fixed everything perfectly I would still wear them as I am accustomed to always having something between my eyes and the world.
It would certainly make getting into position for the shot easier, but I think I'd still struggle without IS, even at faster shutter speeds. It's OK for you young lads with steady hands
When using pure flash (or bright sunlight as fill) you work at your x-sync speed (1/200 or 1/250 w/ Canon) and IS should not matter at that point.
I also use the the servo focus mode which at macro distances serves as IS for forwards and backwards shake. The only problem with this is that the subject is always dead center in the frame. But with modern DSLRs and a good sharp lens there is always room to crop. The whole usage of tripods and manual focus for macros of live subjects simply mystifies me as it means getting way less in focus shots of the subject. Tracking autofocus (AI-Servo on Canon) is way better at tracking a moving bee/wasp/damselfly/.. than manual focus will ever be.
One Shot autofocus mode is still more precise than I can manually focus using the center autofocus point (it is a cross type sensor on all modern Canons) and can be useful for pre-focusing to catch insects in flight.
I should note I am a very modern shooter and favor controlling the light whenever I can over using a tripod. Truth be told, my tripod is currently configured with a lighting boom holding out a 12x18 inch (30x45 cm) softbox which I use in the field with a flash and a wireless flash trigger to control the light for fungi and such. I use a small 4x8 inch (10x20 cm) Lumiquest Velcro on softbox on a 550-EX mounted on the camera when stalking insects as it is fast, portable, and highly diffuse* for small creatures.
I also carry a small collapsible reflector that can provide fill light in daylight or flash-light if needed.
I should note that this technique is highly reliable and results in sharp, low noise images far more often than a tripod as the stalker gets more shots than the waiter. The usage of flash mixed with AI-Servo autofocus tends to negate hand shake in everything but bright sunlight on highly reflective surfaces (i.e., the chitin on a ladybug/ladybird).
enjoy your day,
Sean
* This is like using a 10x20 m softbox to photograph humans if the subject is a European Honeybee (Apis meliflura) to give a sense of scale.