My very first bit of advice is PATIENCE!!! I KNOW how stressful problem feeders can be, but they really are just fine for quite some time without eating...so just be patient and try to not stress them out.

And I would also suggest not force feeding until they have lost significant weight. It is fairly common for one or two from a clutch to not eat for a month or two after hatching...no worries. I just had two eat for the first time since they hatched back in April...no worries. And from my past experience, even if they were hard to start, once they get going they are usually never a problem again. Since you have attempted assist feeding already, I would personally leave those that you tried with alone for at least a week to 2 weeks before offering anything again to get the stress levels down.

Yeah, either try pink rats or mouse fuzzies/small hoppers. I think overall the food item that I have the most luck getting carpets to take is a mouse fuzzy or small hopper. Although they will take rat pinks, they almost never take mouse pinks, so I wouldn't waste my time with mouse pinks. And even though the mouse fuzzies/small hoppers or rat pinks might seem large...don't worry about it. They can handle them just fine.

Good luck, and keep us posted!!!