Hum... the vetch will spread, garlic will be planted lower than either, but I see what you mean about next spring when the garlic makes it's appearance the rye will be tall, and all of this could be thick.
You know for what your using the rye for, ground cover - green
compost, you could trim it right before spring warming. I know garlic will come up through a few inches of growth with no problems. Whatcha think?
Also mark where you plant the garlic and if it is not sprouting in-sink with your other spring root plants then thin the vetch/rye in that area. Leave a little, take a little and that should allow enough heat in to signal your bulbs.