Opinions on Chi Infra High Lift? Or alternatives for single process base 5 to 8?

I know I should be able to go from a 5 to an 8 with a 30 vol and most colors, but my recent experience with Wella Illumina was a little disheartening (I can't post links yet cuz I'm pretty new here, but I think a full exposition on that, with photos, is the next post below this, entitled "Koleston Experts...").

I went with Wella Illumina 8/69 and 30 vol, but the strand test I did hardly lifted at all. Maybe a slightly light 6? I think I want to avoid Wella; they certainly do run dark, and if the goal is lifting, it's prob not the best option. Additionally, I'm really not sure that I'm a 5--indeed, my stylist says I'm closer to a dark 6 (feel free to check pics in above post and give me your opinion), but the total failure with the Illumina in a 8 depth, I'm looking at different options.

I really don't want to go any higher than a 9--an 8 would be ideal. And I want to avoid using 40 vol if possible--hear so many "don't do its" everywhere, it just seems like a bad idea (altho if necessary, I'm willing... I have a pixie so I'm not that attached to my hair, and actually the cuticle could use some "damage": my hair is slippy fine and roughing it up would give me a little volume).

But wondering if I should:

Try a high lift color? Specifically, the Chi Infra High Lift Color... it's ammonia free and a miracle product to some (it seems). Supposedly can lift up to 9 shades (!!), and given their formula, I could use a 20 vol and up to 4 levels up (see attachments for specific info on the line). The other high lift blondes that are safe for base 5 and darker (there aren't many, I understand, but they include two by Joico, L'Oreal Majirel, and Goldwell Topchic).  Does anyone have any experience with this, especially in using it not to go platinum--just to do a single process blonding? Or have any feedback at all? I will say that a lot of the pros on Salongeek have good things to say about it...

Stick with the Wella (or go to a different brand) and try a 40 vol? Or try a "color booster"/base breaker before trying again with a 30 vol? I know the bulk of the lifting power is in the developer, but does anyone know of a brand that has better lifting properties (maybe more opaque) than average? I'd even go with a "light looking" 7 if there's one out there...

Try what I'm going to call "single process bleaching"? I'm really ignorant about this, but it looks like both Wella (Blondor? or Magma?) and Redken (BlondMe) have bleaches that can be used directly with toner and color... I might well be wrong on this since I haven't really looked into it.

And for anyone who wants to know why I don't want to do a DIY double process: my only experience is with box. I'm disabled and poor, and for the sake of upkeep, I really want to keep it as simple as possible.

So if anyone has a recommendation for my quandary, I'd love some input.

Oh... also: if you're interested in learning more about the Chi, there's a youtube video from a waaay fake looking platinum; you can search "Chi Infra High Lift Hair Color Review and Results - No Bleach!". Now, the color totally puts me off, but it isn't per se a bad color--just bad on her IMO. I'm looking to use a 20 developer; she went whole hog with a 40. Anyway, it's long but a good overview of the product, and she seems to know her stuff.

I'm also attaching the company info, a review from a stylist who specializes in "safe" colors (low ammonia, etc.), and a blog post.