Red Grandis is seemingly this timber, not particularly nice to look at,
nor very hard.
https://www.ukworkshop.co.uk/thread...it-really-cost-effective.108026/#post-1176586
Not heard of Gombe before.
Now, the issues of work-ability to me, doesn't have any factor.
That's only when you encounter much tougher stuff, like the Auzzie eucalyptus timbers,
or Shedua type hardness.
That's not very common really.
Some folk mention Iroko as being hard to work, and indeed I used to think it were more difficult
to plane, i.e tool going blunt after 20 shavings, but that was before I learned how the close set cap iron will protect the edge...by a huge amount, that is.
When the cap is working, the shavings will not be curled, but straight.
David W, and Derek have articles which won't set you astray on that subject.
Similar deal with chisels, just aim out of the cut.
Use a drill for the majority, I've never seen a real need for anything fancy,
and buy what you would like to see on the finished article.
All the best
Tom