ok I took screen shots and timed it as well as got the exact amount I made in one trip.
I left one tree on the West side and one on the South...I run down the center grass then over to the left so as not to scare anything off...in this screen shot you can see the tips of each palm tree:
Here are pics showing each trees location from the hut:

It took me 35 minutes total and I made 367,000 bells
Goliaths are worth 6K
Elephant, Atlas, Cyclommatus are all 8K
Golden and Hercules are 12K
I must also note that I caught 2 regular sharks, a hammerhead, 2 whale sharks and a napoleon fish as well. Those range from 8K - 10K
- - - Post Merge - - -
I generally scare off the goliaths or pocket them and replace them with golden stags...I know they are worth something but think of it this way...if you catch 5 goliaths at 6K that is 30K but 5 golden stags at 12K is 60K a difference of 30K I catch at least 6 or more goldens on one trip. I would rather scare goliaths off and make more...even 2k more from other beetles can still net you more bells.
I run around and scare off every other bug and catch any sharks I see as well as BIG shadows in the water...they usually end up being blue marlins or napoleonfish which are 10k a piece! Everyone has their own way but that is how I do it.