I wouldn't recommend doing it again.I had everything with me (was mobile at a friends house). I have never done it before and was with a friend who says she does it regularly at her salon. I work alone so I suppose I wanted to try it out whilst having the input and agreance of someone else with me.
She actually mixed it with 1.9%@Olive293 The reason that you generally don't want to tone with highlift is that by running a product that is so alkaline over hair that has been already lightened you are over lifting the cuticle and eventually it won't hold onto any colour. If you are mixing it with a high developer like 30 or 40 vol you will also eventually sensitise the hair making it weaker and prone to breakage. If you were toning a full head lightener it would likely also cause scalp irritation.
So preferably once you have achieved your desired level of lift with your lightener you would tone with a demi permanent, especially an acidic demi. If you dont need to lift the hair anymore then you don't need something so powerful.
However there are times when you might tone with a permanent colour (although I have never gone as far as highlift) - if you want to actually create more lift. But don't rely on using them to lift, it is more gentle and predictable to lift the hair correctly first with lightener. It looks as if in the photo the toner actually shifted the colour to a lighter level. But next time I would refresh the tone with a demi shade. Also remember that permant toners will lift the natural hair at the roots if you are highlighting.
A very very long time ago when I was less experienced I would prelighten a friends hair and then tint it with majirel 10.1 or 10 1/2.1 + 20 or even 30 vol. And to be honest it was the whitest hair you have ever seen in your life But of course wouldn't do that today.