I would much rather you use a thermos of hot water than to chew the tubing. Many smaller operations use that method. If you do, try to hold the 5/16 at a angle (45 degrees or greater) and only put the tubing in about 3/4" deep on the deeper end, this will leave the tubing more able to be pushed on because one side of the tubing will still be cool.
The next option I'd suggest, is either make a 2 hand tool, many on here have done that.
The next is to buy a 1 hand tool. I do my repairs entirely with a 1 hand tool and a piece of parachute line when pull is needed. I just tie a pipe hitch on the tubing and tie the other end either on a tree or to the other end of the line being connected. Then I pull the 5/16 to tighten the line and slide the pipe hitch to hold. Look up a pipe hitch, it is very simple, even 1 handed. My parachute cord I use is about 8-10' long. It carries easily and weighs almost nothing. You could easily buy a 1 hand tool and use that trick to assemble your system. A 1 hand tool runs about $100. Another option is to buy a basic 2 hand tool, they run about $150-200, bit is the deluxe models with automatic adjusting pliers. A nice feature but certainly not required. Another option, if you don't weld, is to find a friend who will make one for you, you supply the materials and some syrup, with the promise of more syrup in the future. To make a std. 2 hand tool, you can build one for about $50-75.
Dave Klish, I recently bought a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.