SUSIE'S REPLY: Hi Colin,
You might want to try another brand of paper. Just because the weight of the paper is 140# does not mean they share the same equality. Bumping up to 300# Canson will not guarantee a better outcome.
The sizing and cotton pulp is the same in the 140# and the 300# of Canson.
Try Arches 140# CP or Stephen Quiller 140# CP by Richeson
Both of theses papers will hold up when soaked in multiple applications.
I hope this helps!