I think the "no insoluble cones" rule is more for people who do not poo at all. And I think not pooing at all works more for those who have extremely tight and dry curls.
I co-was on some days, but I typically low-poo 2-3 times a week. I too use a mild SLS poo once in a while to clarify. Usually I do a pre-poo with it, and add oils to the poo itself to help prevent stripping. And it's typically followed up with a PT/DT. So I know if I were to use cones it would not an much of an issue for me. I think as long as you low-poo with a surficant once a week you won't have much issue with build up, if any at all.
I think with a lot of the general market poos and condishes, the shampoo AND the condish have cones - typically more than necessary. Plus there is more SLS than needed, and people are using them daily.
As with most things, moderation may be key, here. As long as the cones are removed once a week or so, and you aren't layering cone upon cone upon cone, there should be no problem.
Moderation and technique - those seem to be the keys!
I've been considering giving the new GFTN a try, and using Infusium 23's LI to sort of "super soak" my curls. We'll see. Maybe I'll experiment and report back!
2c/3a/3b, Fine/med, Dense, high porous, & normal elas.
Lo-poo - Renpure Keratin, SMR, Giovanni SaS
clarifying - mix Johnson's H2T with low poo
Co-wash - Suave Nats. clar. or coco.
RO - GVPCB, Ion Eff. Care, TN.
LI - SMR, Cure Care, or RO
Seal - MO or Jojoba
DT - + honey, ACV, & EVOO to SM masque & GVPCB
PT - Gelatin!, CNPF
Styling - FSG, AIF, BRHG, LALS/PS, GF curl spray gel, SM Souffle/Smoothie, LOOB
Oils - MO!, EVOO, jojoba, GSO, SM Elixer, EVCO, VO5 Hairdressing