Ebay water nipples

[Bigrig]

I am still pricing out the equipment I need and contacted an ebay seller regarding the water nipples he was selling. I noticed he had nipples with grey, red and yellow plastic "barbs" and wanted to know the difference. Trimmed for brevity:

From: rabbitfeeders
Are you talking about the internal spring or the mounting springs
Mounting springs are all the same internal springs are the same but a few of the nipples are adjustable. So you can make the trigger a little stiffer.
The yellow barb nipple don't use a internal spring they is a diaphragm and are not adjustable.

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Dear rabbitfeeders,
Is there any difference in size/spring tension/etc. between the nipples you
sell with red, grey or yellow plastic fittings? I see they are all listed
for 5/16" ID tubing.

After getting his reply I actually watched the youtube videos linked in the auctions and he already explains all that . Basically:
Yellow = diaphragm (easy to disassemble).
Stainless (I called it red because of the red tee) = spring adjustable.
Blue (I called it grey) = spring (easy to disassemble), and he mentions a light touch good for baby rabbits.
(I think I must have been going colorblind!)

I assume ALL buy-from-china sellers stock would be essentially identical. Now if they only didn't use 5/16" tubing! I now know the difference between them AND learned that not all youtube links on ebay are just advertisement.

Now for my question, does it make sense to place multiple nipples in each growout cage? On the one hand it gives a backup if one sticks closed. On the other hand it won't help if the other breaks "open" and drains the reservoir.

Thank you.