36 foot??!!! LUXURY!!!!
When I were a lad we 'ad 30 foot an' were grateful!
An' whats all this prattin' around wi' bikes??? Pah, in ma day it were all on't foot!
Seriously Crispin, this is all about slow and steady. I would not worry about racing speed. The fact you are a runner will give you all the ability you need on the day. You might run 20 minutes faster than another team on one running leg only to see half a day go to pot on the next sailing leg!
As others have said, the ability to have almost a telepathic relationship with your running partner and a willingness to muck in with running the boat are probably the most important things. You WILL get into the most unbelievable scrapes and you WILL have tales to bore your grandchildren with!