Since you are in Michigan, because of the cold winters, there should be some space left between the insulation and the roof decking. With gable vents installed there’s no need for soffit vents, however, if you fill the sides of your attic with insulation all the way up to the rafters / roof decking condensation may start developing when temperatures drop below freezing.
What you can do, instead of installing rafter baffles, is to get some blanket insulation (un-faced), cut 12”-24” long pieces and slide it (push it with a stick if unable to crawl that far) towards the corner where the attic’s floor meets the roof framing. That way you can better control the air gap. Whatever area you have left can be filled with blown-in insulation.
A couple of tips... be extremely careful with that vermiculite insulation because it might contain asbestos. It will be impossible not to disturb it while working there and pushing those pre-cut pieces so make sure to wear an appropriate respirator mask (not just a dust mask) and eye protection!.
Always assume that it contains asbestos unless it was already lab tested and proven otherwise! Wear bosy protecting suit / gloves and seal off the house access to prevent any possible contamination. Wait for a cool weather.
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