That one semi hidden 10mm is a bitch! I ground down a 1/4" 10mm socket to fit, can't think of anything else that would work.
As far as the seal itself, easy peasy. Just insert the pushrod barely into the seal use it as a lever to pop it out. It's held in with almost zero pressure, doesn't take much. Put some oil on the new one and push it in with your fingers.
Current: '15 Tenere ES - 30k km
Past : '06 FZ6 - 115k km, '06 KTM 625 SMC - 30k km, '06 V-Strom 650 - 80k km, '07 FZ1 - 70k km
“Instant information is instantly obsolete. Only the most banal ideas can successfully cross great distances at the speed of light. And anything that travels very far very fast is scarcely worth transporting, especially the tourist.” - Ted Simon, Jupiter's Travels