I've become quite partial to really strong sencha. But whoa, was I surprised tonight. They're not kidding when they say "drop by drop", because that's all a person can take without being knocked off their chair.
Hehe, i would not be able handle this either, even "drop by drop"
Recently i tried to prepare some koicha, 4 bamboo spoons of matcha for 70ml of water. I didn't really feel noticeable bitterness or astringent taste, but still it was like explosion of flavors in my mouth. Don't think i will do it anytime soon again, i prefer lighter version with foam. Probably it's really similar to your gyokuro experience
Try once with half of recommended leaf ratio, maybe you will enjoy it more.