Non of them are stronger actually... The problem is, that you didnt knew how to use the right pistonclip and how to install it correctly.
First you need to know the size of the pistonpen that goes through the piston.. There are differents types available..
Some engine uses Pen 10, Pen12 or even on 4strokes Pen 13.. And then every piston uses its own version of circlips.. Some circlips are thicker then other ones which are smaller.. Also when installing an circlip you have to check it right if the clip is installed right in the groove of the piston.. You really need to feel or hear that the clip just snaps in to place..
If you are unsure if it is installed right. Like clip number two you can grip is with pliers and just turn it a little bit slowly.. So you can see the whole clip is housed in the groove totally.. And then nothing should happen about clips came loose an would getting destroyed in a ruining engine..
And also a good guideline is.. Smaller clip goes in smaller groove, thinker clip goed in bigger groove. You cant use a thicker clip in a smaller groove, because it wouldnt sit correctly, and the chance is big that it would sping out. And a good idea is, dont reuse old installed circlips again, use new ones instead, because an old clip could have less tension and can get weak after using (change of breaking is also an option)