got email back from the supplier. the insole widths on the 43e and 44 for the shimano rx8 are pretty much the same. the 44 insole is about 0.8 cm longer. So it appears that the sizing for 43e on the RX8 mirrors that of the R321's I have. so that's the size i ordered. thanks for the lake suggestion. But i've had good experience with shimanos. I especially like their adjustable insoles. I have high arch, and their insoles are great. no need to mess around with aftermarket insoles.