I was looking for a solution to this as well... still haven't found one but I should point out that I currently use a pipe and structure rule to help with this...
It's specifically for Watermains. We prefer to use gravity pipes for watermain and center to center match makes more sense for watermain design. So I have a pipe to pipe match rule that uses centerline with a drop of 0 and a drop across structure rule which also uses centerline with a drop of 0. The first one is really for the initial layout but if you need to resize, then you can just apply the structure rule to the junction and the pipes will adjust for you based on center, invert, or crown (whatever you've specified in your rule). Obviously flow direction has an impact but in general it has worked well.
I hope that helps but, yes hopefully an option to set resize location in your parts list would be preferred.
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