Why do you need to use rubber tube?
The rubber tube gives a wee bit of give to the rope. I have tied hard and solid alot of times but if I have a real fighter I would prefer the slight bit of give using and inner tube.
To me the best, bar none is a high line. It is a heavy rope strung between 2 trees about 8 or 9 feet off the ground. In the center between the two trees you have a loop to give you a place to tie the line from the horse to the high line.
This high line is stretched as tight as you can make it and tied off around each tie securely.
I then use a neck rope, not just a halter and lead shank and tie the horse to the loop in the center of the high line.
The horse can not break the high line because it has give. The trees sway with the pull, the horse can't run into anything by pulling back and then leaping forward. If it throws itself it can't hit anything except the ground, not to thrash against and it absolutely can not break free.
I have left horses high lined for days on end without ever seeing one get in trouble.
All my guys are just tied hard and fast to something about wither height of eye height with a neck rope with a halter with the neck rope passing through it to keep the head aligned with the pull and just let them work it out.
A confirmed fighter might fight too hard so I prefer the high line or the rubber tube for that little bit of give.
I will not pull against a halter and lead. Neck lines all the way.
Sunday morning I can see 100 plus horses tied all in one parking lot and every single one of them uses a neck line, every one