Hey, totally know where youre coming from, one of my teachers a few years back taught me this little nifty trick to solve the problem!
1. Buy the normal A4 dividers - theres no need to fork out extra £ on wider ones. Take one divider and lay it underneath a plastic pocket.
2. Mark on the plastic wallet with a Sharpie or other permanent marker the bit where the little tab sticks out.
3. Take a pair of scissors and cut a little rectangle on the plastic pocket where you've market the little tab. You should now have a little rectangualr sized gap in your plasic pocket.
4. Heres the tricky bit - insert the divider into the plastic pocket, ensuring that the tab slots through the gap you've just cut in the pocket.
5. Place the divider (now encased in the plastic pocket) in the right space in your folder. The little tab should now be visible because it has the same measurements as all your other bits of work (ie they've ALL been pushed out equally because they're all in plastic pockets)
*Little tip* To ensure your tabs dont rip or get folded and tear, cover them with a small bit of laminating tape or Sellotape.
Hope I helped, reply back if you're still confused and I'll clarify