Repairing linen tears

[Jonboy2000]

Not exactly a poster, but as a poster and map fan I thought I would see if anyone has some advice on repairing linen tears.  Where the map has been folded over the years (from 1818), there are now tears in the linen between some of the sections.  The cost of a professional restorer doing the work would outweigh the value of the map. I intend to frame it eventually so it doesn't have to be perfect.  Just wanted to give it a bit more stability
I thought about trying the same method for a paper tear repair with tissue paper.  Just wondered if someone had come across a better product or technique.