So what else is there (other than resistance, inductance or dielectric) to consider?Nothing else that I can think of, beyond what we've already said. I don't think that dielectric absorption will be an issue. The electric field between adjacent paralleled cables will be minimal, partly because of the one-inch distance, and partly because of the cancellation resulting from the twisted and braided construction of the two conductors in each of the four paralleled cables. Also, depending on which of the two physical configurations I asked about is used, the dielectric between paralleled cables may be mostly air, which as I understand it has essentially no susceptibility to dielectric absorption.
Total capacitance (between + and -) for a 2.5 meter run (about 8.2 feet) would be 1448 pf, somewhat on the high side but I suspect still low enough to not have audible consequences with the great majority of amplifiers.
Best regards,
-- Al