I've read many different things about feeding goldfish. Some say feed only as much as the size of one eye, some say feed as much as they can eat in 2 or 3 minutes, I've even heard 5 & 10 minutes. Firstly I'm not sure which of these suggestions is best and secondly they raise other questions. For example, the time limit ones, I have 2 fish that are very fast, accurate eaters & complete piggies (would stuff their mouths full & not be able to close their mouth if allowed), my other 2 fish are much slower & less accurate (vision & swim bladder issues respectively, plus they like to savour the food, take a mouthful & go for a swim while chewing before eating their next piece) and so would eat considerably different amounts in the same time. The size of the eye one doesn't take into account the thickness of the food, say seaweed sheets or flakes versus pellets.

I have 2 large orandas (hard to measure but say about 5-6 inches including tail) & 2 small ranchus (actually I think the pet shop got it wrong & 1 of them might actually be a lionhead, about 1.5-2 inch including tail). I feed them a mix of peas, wardley spirulina discs, julian sprung seaweed sheets, hbh vege flakes, hikari goldfish flakes, nutrafin pellets, omega one shrimp pellets, frozen goldfish food. I usually feed them twice a day. I handfeed them whatever food I've chosen to make sure the slower fish get their share and then give them a small amount of flakes to hoover for (it's their favourite activity!). I don't know if I am feeding them too much or too little?
For example, if they are getting peas or shrimp pellets then the big fish would get 2 peas or pellets each and the little fish 0.5 pea or pellet each since they are about quarter of the big fish in size. If they are getting spirulina discs then the big fish get a 1/3 pce each.

Any ideas whether I would be feeding them too much, too little or just right?

Poop can always give you a fairly accurate answer: if it's fat and really long, the fish are eating too much; if you never see the fish poop, even shortly after meals, they might not be getting enough. What you want to see are fat, fairly short poops, which are the same color as whatever the fish have recently eaten.

If the fish finish all of their food, and are still ravenously searching for more, then they probably need more. If they finish and are just patroling around for leftover tidbits, they're probably fine. If food sits for an extended period of time without being touched, they might not need as much. Of course, this all depends in part on the fishs' personalities--I know what you mean by piggies and savourers. I'd say the poop is likely a more reliable measure.

I've got a 6+ inch ryukin, a 5+ inch oranda, and two 5+ inch telescope-eyes. I feed them twice a day, and this is roughly the amount of food they get with each serving:

Breakfast everyday: 1 cube of homemade gel food, roughly ¾ inch square and 4mm thick (they're getting large enough now, though, that I think I may need to increase the servings)
Peas dinner (3x a week): about 4-5 (give or take) per fish
Pellets dinner (3x a week): ½ slightly rounded teaspoon
Wafers dinner (1x a week): 6
Duckweed (1x a week, in addition to other foods listed above): however much I can scoop out of my tropical tank, and probably a few pond snails along with it

When they were younger, I was feeding them with a range of 15 minutes. Back then I had a gravel bottom, so they had to search more for their food, but I've since switched to bare-bottom, so they can finish quite quickly. As you said, the typical feeding measurements have their flaws.

Thanks SnBMeg. Sounds like I might need to feed my big fish more, so I'll give that a go and see how they respond.

I think it is very helpful to read posts like your reply where someone is actually quite specific about the size of the food, quantity given etc in relation to size of fish. Much more useful than the usual time guidelines etc. Hopefully, even more people might respond with their feeding routines. Thanks again.

BTW the 3rd fish (blue & chocolate oranda) in the pictures at the bottom of your post is stunning!

I hear ya about the time guidelines... my bigger goldies could eat an entire bag of progold in 3 minutes if I let them. It might work with some, but the bottom line is that you have to get to know your individual fish and their needs by carefully observing them.

Another way to get them more food is to nuke a couple pieces of veggie in some tank water, throw a plant anchor or veggie clip on and toss it in. My fish entertain themselves with big hunks of squash and other veggies during the day while I'm at work. I know they aren't bored and that they are getting lots of fiber.

My orandas are eating a lemon slice right now and the faces they make from the sour taste are so funny. Minced garlic is equally funny - they make that "O" face