Sorry I don't shop at Walmart or use vermiculite
I've cloned 1-2 inch clones many times with no probs, but those 3mm fatties are a pain. I don't get the science behind why its a prob. That does look pretty spliffy tho.
...no offense bro but that is a bit of a bullshit answer 'i don't shop at Walmart', ...i mean really man, didn't it occur to you that you might find them elsewhere?
Ice Tube Tray
Ice Tube Tray
...and if vermiculite is a problem for you then coco can be used but the details are a bit different.
just so you know, i linked you to that thread because this is a very simple cloning technique that once mastered it will give you the skills to make any cloning method work for you, ...this simple wick style technique was introduced to the canna community some 15 - 20 years ago on the old Overgrow site, before they got shut down, and so it has stood the test of time.
...and like i said, it's easy as shit to learn and to run and it's also cheap as shit to run. ...and 80 - 90% success for even a first timer is easy to achieve.
anyway, taking large clones is a mite trickier than small clones because you have so much more vegetation but it can be done, ...here's a couple i cloned directly into 9oz solo cups of coco as i prepare to pot them up into coco hempy's, ...as you can see they are quite large.
...and here's a shot of the rootmass.
...cloning is a skill bro and you hone your skills through practice, every run is practice for the next run, ...and while there are many different techniques, all become easier to master if you first master this SIMPLE method, ...frankly, i retired my bubble cloner that worked very well for me for more than a year after i started using these Ice-Tube-Trays, ...that was like 4 or 5 years ago now.
anyway, good luck with whatever method you choose, may you succeed beyond your wildest dreams.
peace, bozo