Mad Space is quite tough. In fact, I remember getting my final emblem just by A-ranking the fourth mission on my first playthrough. Its gonna take a lot of patience and flying around, but good luck.
Yeah, its really ironic that the "hard modes" of the treasure hunting levels have the items in the same locations. Those locations are only unique to the hard modes and while some are a bit tricky to grab, once you find a way to obtain, they become easier than the first missions.
That's odd. Even with the earlier stages for Sonic and Shadow? Now Final Rush and Final Chase, those are understandable. Bottomless pits everywhere.
Gotta love shooting shit up in the Tails and Eggman stages.
Unfortunately, the requirement for getting an A in Metal Harbor is to take the longer path once you reach the rocket and the countdown begins. This video
does show a way about how you can reach the top part of the rocket with a nifty shortcut a lot of people overlook. It might take time to master like everything else in the game though but fortunately Metal Harbor is super short and isn't that much of a slog to me either.
It was the main draw to everyone back then and I believe they really helped the Adventure games' replay value. But I think that's why they were eventually removed, because the Chao Gardens were meant to be a smaller part of the game compared to the core gameplay which I think Sega wanted us to remember the most.
Regardless, I liked raising my MLP-themed Chao back during my second playthrough. I never finished my second playthrough because I sadly got all of the non-Chao emblems. So if you at least play through attempts where you don't get the A-rank, you'll at least have some Rings, small animals and Chaos Drives to continue grinding your Chao with. Something I should have taken to mind years ago.