When you ship by sea, you usually pay by the container, not by weight. In other words, it's a flat fee per container. Whatever you can fit in a container (20ft or 40ft) is the same price as long as it fits in there. I know people who ship decorative river rocks from the Philippines to Hawaii. Same price as container of bamboo furniture which is much lighter.
Shipping from Philippines to Hawaii is in the $3000 dollar range per container YMMV.
Also wood isn't sold by weight. Its usually sold by the board-foot though I dont know about in Africa.
I would try to buy it by the "container load" ( in other words, as much as can fit in a 20 or 40 foot container), since that is a standard unit of measurement and is a handy reference and unit of measure for negotiation that all sellers will be familiar with.
Teak like all fine woods, comes in various grades. FEQ (First European Quality) is one high grade of teak that your supplier will know about. Teak Dock Grade is another.
Some links of interest:
Also please know that African Teak is not true teak (Tectona Grandis).
Attracted by cheaper production and better margin costs a lot of furniture entrepreneurs have recently started to buy so-called teak wood coming from Africa. Do you really know the ugly truth hidden behind “African teak’s” production?
Pericopsis Elata or Afrormosia is the scientific name for “African teak”. Found in various countries such as Cameroon, Nigeria, Ghana or Congo, this similar-looking wood is in fact not true teak. The tree is a timber species that belongs to the Fabaceae family. Its illegal logging and unregulated trade is ranked CITES Appendix II (Threatened species). Also known as Convention on International Trade in Endangered Species of Wild Fauna and Flora, CITES aim is to ensure that international trade does not threaten the survival of the species in the wild.
Database on afrormosia (African teak)
As normal, all this is discover, and trying to know the difference between what we read, and what is real. This is what I love about Africa, or World Travel.
This site talks about the history of Teak in Togo. http://www.itto.int/sfm_detail/id=12360000
"The most important commercial tree species is Tectona grandis (teak). Teak plantations were introduced
in 1910 from Burma by the Germans and have become well adapted to the country. The species regenerates naturally and is widely used in agroforestry plantations, as street trees and in commercial planted forests. A silvicultural system to induce natural regeneration has been developed by ODEF and is practised in some of the older teak stands."