I used Tygon 7/16 R3603 and I hand tightened them.. Believe me when I say just pinching them up with fingers is sufficient.. you can't pull the tube out lol.
If you fancy the Mayhems Gigabyte Orange, I highly advise picking up a bottle each of Yellow, Orange, and Red dropper bottle dye. It's a bit of a weak colour straight out the bottle, nothing like any of the product shots show at all.
I got mine filled and was quite disappointed, emailed them direct after having a chat with Ayd at Specialtech and got a yellow and red in the post completely free which arrived in a few days, super impressed. A few drops of yellow to sharpen the colour and red to deepen it and it's much more like what I wanted.