The front uses the same length dogbone for the e/t maxxes; 57.5mm. There's a bit of play so you'll need to put one o-ring for each cup. 59mm would be the ideal length if you decide to have one made by RCalloy.

I can't see the picture from work.

Cool!! I have a few extra front stock length ti shafts.

Besides
 

Besides the O-rings you can also use some silicon fuel tubing to buffer the gap in each drive cup. It really does the trick and since you are still a nitro guy I am sure that you have some laying around. Good to see that you are having fun figuring this build out for BL. Have a good one.