Climbing Mount Shasta with MicroSpikes instead of real crampons?

I'm planning on hiking up Mount Shasta (avalanche gulch route) this June. A lot of sources say you need fully on hard plastic mountaineering boots and crampons to make it up there, but a friend of mine who has done it a few times says he's not sure you really need those. I just have regular hiking boots and I don't want to have to buy/rent mountaineering boots unless I really have to. There are some less-hardcore things called MicroSpikes that will go onto the normal hiking boots which should still increase traction in snow/ice and have pretty good review, but are they good enough for Shasta? Apparently it gets up to as much as a 60% grade in some spots and is generally pretty steep the entire way. What is the steepest terrain that MicroSpikes are acceptable for?