Does anyone have experience with low temperature prepreg?

I am using a water-soluble plug material that gets a bit soft at 75c (the lowest I can test at the moment) thought the melting temp is somewhere around 200c. As the solubility of the plug is essential to the design, I am looking into lower temp prepregs. The complexity of the part makes infusion difficult in both the multi-layer layup as well as proper resin coverage under vacuum. 

Thanks

it could cause pinholes depending on if you are doing an envelope bag, and also how good the vacuum is.
Do you  have any pics?