Sorry it took so long for my resonce, We just got back form holliday.
1) The rope length should be about 200' total. First part of the rig is a Nylon brade. Two legs running to your 60'. At the end of that a 100' Plasma Hawser to a snap shackle. Then a 10' Pendant that is attached to the toweye with a BOLT TYPE forged shackle.
2)outboards up? thats hard to say, half of my customers put the motor up and the other half like it down for better tracking. they use a motor loc to keep them from flopping from side to side. I think for a long hull, up is the way to go, but for short runs down would be fine.
3) your towing speed depends on your HP of your 60' and the seas. on a average 18-22 knots. but every boat reacts different. How close to the water line is the tenders toweye? how loaded is your tender? These things all effect how the tender reacts behind the 60'.
If you goto PAGE 2 on my site, then goto the bottom and click the more info link, this will show you a layout of our towing rig, and if you have any firther questions or concerns, Please contact us.