I have found livebait the best method to target tiger where i have fished (mainly in Zambia - Luangwa, Zambezi, Kariba plus Cabora Bassa) BUT they can be difficult to get hold of, and depending on current and rigging they can die quickly - this sometimes does not matter - depends upon how the fish are feeding..
Imberi are great, along with small nkupe/chessa/tigerfish - but not very tough - tilapia better in that regard - you can even rig a small squeaker for big tiger - break the spines off, hook behind the dorsal fin etc.
RF