Hmm, how much thicker?
Mine are about 1mm - or 1 washer thicker. The only important bit is to ensure that the feeder hole lines up with the hot end tube.

Might be worth a little tweak and a play to make them fit, as I think they will solve your issue.

Failing that, I would imagine that the all metal ones will be a better fit, as they are milled out of standard thickness material - as is the heat block. The chances are they will fit properly. Find ones with good reviews.

On another note, check that the thermocouples you bought are insulated. Many are not, with the junction just crimped into the eye. I took mine apart and insulated them with some high temp sleeving. If not, you will find that the heater temps will be all over the place, as the thermocouples will be connected to both the heater blocks!