I think these are the fish in your 180 gallon right now?:
3 silver sharks
1 rainbow shark
1 upside down catfish
16 neon tetras
1 neon blue gourami
2 female guppies
4 angels
3 clown loaches
2 blue ram
1 bristlenose
I don't agree with most stocking level calculations. The problem is that you have to consider a lot more than just adult size. For example, aggression, territories, activity level, how 'dirty' they are (take goldfish or plecos lol), water requirements and environmental prefferences.
Bala/silver sharks grow to 12 inches but I would never keep one in a 65 gallon tank. The reason is that, though it would be large enough to accomodate one, it would not offer the necessary swimming space. The same applies to fish like zebra danios but at a much smaller scale. I wouldn't keep one in a 5 gallon though it would easily have room to grow to adult size. Plus both species need the companionship of their own kind.
BTW, the 200 gallons you read about would not be for just one fish - it's just what they require to be truly happy. Again, using zebra danios as an example, you could have 5 in a 10 gallon but 10 in a 20 gallon would be much much happier because of the swimming space.
However, I think the three bala sharks you have at the moment should be ok in your 180 gallon tank. 200 gallons, after all, is only 20 gallons more.
It's always advised you calculate your tank size based on the adult size of your fish. But the bala sharks & clown loaches will take a few years to reach that size.
Ok, this is something I will have to comment on. I realy don't agree with keeping large fish just because they grow slowly. You should ALWAYS base your tank's occupants and stocking on the ADULT size of the fish. That would save a lot of fish lives and suffering and fewer would need to be re-homed or returned.
You could probably still put a few (smallish - no more large) fish in that tank. I would recommend some more gouramies (they are dwarfs right?). However, I'm a bit concerned about certain things - angelfish will eat neons very readily at adulthood (that may still be in a while and a large tank may allow your neons to escape but there is no denying that neons are an angelfish's natural food in the wild so...). They may also eat your guppies but, as they are female, they should be large enough and quick enough to escape.
As for the 8 gallon, there is a HUGE selection of fish that can go in there!
You shouldn't keep to bristlenose plecos in a small tank - they will fight. Plus pleco are messy fish and you need at least this size tank for just one bristlenose. I wouldn't keep a pair of rams with the other fish you mentioned - you'd be seriously over-stocked if you combined them all. Also, if they pair up, they are still cichlids and will be territorial.
Honey gouramies are colisa chunae (or c. sota I believe) and the males can be rather aggressive. Though they are small (max. 2 inches), I wouldn't keep two in an 8 gallon unless you could find females (which aren't as colorful and are often hard to find).
Honey dwarf gouramies do exist - they are a seperate species (colisa lalia) and are just a color variety of the popular dwarf gourami. These are not as aggressive but males can be very territorial towards other fish of their kind. I think the neon blue in your 180 gallon is one of these (unless it's a three-spot - trichogaster trichopterus). Again, I would only keep one of these in an 8 gallon but you could also include some (3-4) dwarf cories OR 5 harlequin rasboras or black phantom tetras in an 8 gallon (with the gourami).
There are many other options as well. For example, golden dwarf barbs, a bristlenose (just the bristlenose and some tetras though), a pair of rams (just the rams and some tetras) or some guppies, platies or a planted tank with 6 cardinal tetras or harlequin rasboras.
That was one long answer... sorry for rambling on and boring you to death