I have the same properties as you do, except my porosity has improved over time. I can't co wash. I get weighed down too easily. and if I do a PT I don't DT afterwards. I do like the ION EC. One thing I would suggest is using products with protein in them. Usually fine high porosity hair will love protein even in products.
fine, thin, normal/(low?) porosity. Mod-CG. Usually I can't co-wash more than 1x a week, & sometimes I have to use T-Gel in rotation due to scalp issues.

Co-wash: VO5 Volumizing
Poo: Giovanni 50:50
RO:TN, Nexxus Youth Renewal, Alba Coconut
PT: gelatin PT, ION EC
Stylers: Giovanni mousse, TIGI Curls Rock amplifier (a-cone), Curls Rock Strong Hold Mousse
Gels: SCC spray gel