They're a bit thicker and a lot softer than the 2mm Soyos, I've got some of the thicker 4mm Soyos on my Roberts and they're pretty uncomfortable... Kinda like a cheese grater... Strong-Vs are lovely but they're quite pricey IIRC... The Charge Plungers remind me of Champs a lot... I'd recommend them....
They're a bit thicker and a lot softer than the 2mm Soyos, I've got some of the thicker 4mm Soyos on my Roberts and they're pretty uncomfortable... Kinda like a cheese grater... Strong-Vs are lovely but they're quite pricey IIRC... The Charge Plungers remind me of Champs a lot... I'd recommend them....