With a little googling:
+proj=tmerc +ellps=WGS84 +lon_0=29
+proj=tmerc +ellps=WGS84 +lon_0=27
Link:
MapInfo projection and datum types: http://reference1.mapinfo.com/software/mapinfo_pro/english/16.0/MapInfoProUserGuide.pdf
Notes:
- WGS84 and Hartebeesthoek datums are coincident.
- No need to specify default proj4 parameters.