Oh my gosh- you're an awesome mom! You're trying so hard, watching his cues, and really trying different things to see what works! Please, recognize that for what it is- being a GOOD mom!
Your son just isn't one of the easy sleepers. That's life for a lot of mamas! But I personally think you're on the right track, here. Whining, chatting, moaning...those are very likely his settling techniques at this stage. He's trying to avoid sleeping at all costs (most likely because it's way more fun to be with you!), but you know he needs the down time. So I would keep doing that 1 hour (or maybe switch to 45 minutes) window, twice a day. If he falls asleep, then awesome. If not- then go get him. If he really isn't screaming for longer than 10 seconds, then he's ok! Fussing is totally different than hard crying, you know?
In a few months, you may try switching him to one nap. I'm not a fan of doing that for most babies before the age of 2, but some are tough. (Like yours!) So maybe that will help create a longer afternoon nap?
Does he have a teddy bear or other stuffed animal? That helps my son tremendously!
Good luck. I know it's so hard to feel this way, but you're doing exactly what you're supposed to be doing. Listening to both your son and your heart...and you're doing a great job at it!