canvass repair reality check

[cruiserpop]

Am goin to attempt a canvass repair myself, need a reality check
93 cloeman yoesmite (hard side) ended up with a seam tear last time we used  
1. bought a sail palm and various size needles, what thread should be used?
2. will I need to beeswax the seam after I'm done?
2. is a backing cloth recommended?