Size of Fork Seal Driver Tool?

I'm getting ready to change the springs, seals, and oil in my '11 Roadster and thinking of getting the seal driver tool. I've seen the homemade versions, but figure with my luck I'll bugger a seal, spring a leak, and then have to rinse and repeat the whole job.

Question: what size tool do I need? I may get an adjustable one, but want to make sure the correct size falls in range. I also have a '98 Thunderbird Sport, so if the tool covers both it would make the purchase seem even more "affordable."

Thanks

Update- OK I found somewhere where someone says 43mm. Ordered.