adipe

i'm having issues with the inner tube getting cuts by the rim tape which i have cut so that it does not interfere with tire seating;
i'm having issues finding easily a quality butyl inner tube that does not have vulnerabilities - low quality and less resistant to high pressure in these circumstances;

i'm having issues with high pressure - needed to ensure a perfectly seate tire - making dimples in the rim tape;

i'm having 150+kgf DS tension (very small tension variance so it's okay) with the inflated tire because the short spokes on this bike (large hub) permits it and i would not change the Alpine spokes on both DS and NDS flanges that ensure durability to vandalism etc. i want the least vulnerable rear wheel as possible for different reasons;
this high tension compresses the rim so that the tire can be mounted quite easily now using just my hands and no effort with the proper technique;

i don't mind having to use tire levers with a thicker cumulative rim tape.

i'm thinking about adding a 26" tube on the 29" rim so that the ~30mm cut portion would go over the existing tape which does not go over the low bead section so that the butyl would cover all the rim seat and maybe even go a bit above that; it shouldn't climb if in tension (no glued portion of the cut 26" tube, just cut as in half lengthwise);

i guess this would solve all my problems BUT i have to ask: has any of you tried using a butyl rim tape in any of these circumstances?
would the tire be more spongy? it's not an easy thing to do - cutting the 26" inner tube to exact size, mounting the tire etc. etc. etc. so i humbly ask for people in the know about this.

thanks in advance.