Lol smashed miles on that one. I just played green hole and got 3 eggs with gadges in on the first floor but I have only played the level a couple of times so half my dudes got eaten and I couldnt find the key
Fairly simple level. Strat is:
Floor one: Mong the mother bulborbs asap and get the babies for yourself. Don't carry anything back though. Go around egg hunting for gadges. Kill gadges. Now carry everything else back, key, diamonds, mother bulborbs, circle thing and the crystal or whatever it is. If you have spare time like whilst things are coming back then use it to flower pikmin.
Floor two: Spice spray everyone immediately then dismiss them all. Take the reds up to the big dude, bitter spray him then lob about 3 onto him. Kill any nearby enemies. As he is almost coming out of the rock lob all the rebs on to finish him off but make sure he dies and leaves a carcass. Don't take of this stuff back yet. Run into the middle and get the rest of the pikmin. Leave Louie here though. Go around the edge and carry back and kill as much as you can. Once you run out of pikmin switch to Louie and use him to get the nearby stuff from the start. Leave Olimar on the edge bit, standing near anything you missed or if you got everything near the exit. For speed now it is quicker to use Louie to throw pikmin up out of the pool to Olimar who can then use them. Just get everything in etc.
Going to mong more levels now. I now have the most gold medals again.