Hi,
Since lockdown I’ve dug out my twelve year old slackline and been using it out front of the house.
Things have changed since I used to do it – 2inch wide seems the norm now (mine is 1 inch) but all the major brands have a relatively similar ratchet. My ratchet is the same as what is being sold now.
Gibbon seems the well known name but plenty others to choose that’ll do the same job and a bit less price. Just need to check it’s safety rated.
Gap I’m using is probably only 8 – 10 metres but plenty long enough for fun for me and the kids. Slackines aren’t that expensive so (to me) 15m is an ok length to start and if you outgrow you just buy a longer webbing and use the same ratchet as before. But yes, you just use the webbing you need and leave the rest trailing out the bottom of the ratchet so you can have 25 metres of webbing and only create say an 8m line if you wished.
Couple of weeks ago I brought two Gibbon XL tree protectors for under £20. Could use carpet or towels round the tree but I wanted a neater setup so I don’t give reason for the neighbours to moan at me (they always moan!!)