Hi there! Just bought a vintage tri bike with Dura-Ace 7800. Need to replace the crank arms. They currently have 170 and the bike is a very small bike and I am also very small so want max 165. I live in a country where there is a poor selection of used parts as well as a poor selection of "small people parts" so a used 165 crank arm that is 7800 is probably never going to be an option.

I assume ultegra 6600 and 6700 would work? What else might work? Bike is 10sp obviously and I don't know if 11sp would fit on the wheel set and am not really wanting to upgrade the whole thing due to costs. Wondering what my other compatible options are here. Have considered a new crank but again, a new 10sp crank that is compatible with 7800....? Looking for options I guess. Hate to ruin that it's all dura ace gruppo but in this case, it is what it is. Thanks.