Tohuwabohu excorcism

For sync and merge - use TortoiseSVN and P4Merge as external merge viewer.

How to integrate P4Merge into TortoiseSVN: http://1024strongoxen.blogspot.de/2011/08/three-way-merging-made-painless-with.html

Add in the External Programs / Diff Viewer the path with these args:
C:\Program Files\Perforce\p4merge.exe %base %mine

And in the Merge Tool section:
C:\Program Files\Perforce\p4merge.exe %base %theirs %mine %merged