Wood drying in the tropics is definitely different, with pluses and minuses compared to the temperate zone. What's your weather like: wet tropical or dry tropical? Rainy season every day or a distinct season where it rains followed by a distinct dry season, because that impacts on kiln performance, particularly with solar kilns.
I'm in the wet tropics of Australia, and used to drying large tropical hardwoods. Different species but same kind of density range and sizes. Couple of pointers for you.
End sealer is your friend and you need to apply it to the ends of cut logs as soon as possible after felling the tree for it to really work. Then again later with valuable species just because its cheap and good lumber is worth the extra insurance. Water just about runs out the ends of tropical species when freshly cut but once that initial moisture is gone they will start to crack if some precautions arent taken
Generally speaking when its hot I need to slow my initial air drying rate down on 3" lumber, usually by putting the sawn timber in a place with lots of ventilation but not much airflow. If it dries too fast it develops micro checks that you cant really see but that later blow out to large cracks.
Mostly wood will go from green to 20% MC in a couple of weeks. Thats the point at which all the free water between the wood cells has ran out, and what we're left with is the water inside the cells themselves. At that point I will rotate my stacks of lumber into a place with better airflow.
I like to airdry heavier lumber like that for mostly 6-9 months to a year before going to the kilns. If it's really figured and I'm worried it will be a problem child to dry I give it longer.
Passive solar kilns like the Virginia Tech design can do well in the tropics, sometimes. Much depends on kiln design and your climate: I've seen some work and some be not so good. Here where I am they will do well in winter but not so good in summer which is our wet season.... because it's stinking hot so the kiln runs hot and pulls a lot of moisture out of the wood but the high ambient humidity means theres no-where for the moisture to go, and then a shower of rain comes over, the kiln cools and the humidity stays inside and condenses back over the wood. Down the coast from me 100 miles in the dry tropics passive solar kilns work great but need care in summer because they sometimes work too well, but that extra 100 inches of rain we get makes them a fail here for half the year.
Hybrid solar works well here.... using the sun to heat water to heat the kiln. Have a look around these guys website:
http://www.solardry.com.au/solardry/10m.htmlFriend of mine has one of those and it's a champion, however he's on top of the range so in winter he does have to use the gas boosters a bit when its frosty outside. If I had one of those here it wouldn't need that because I'm on the coast so our winters are still warm.
My own kilns are DH units. They work well, but I have an electricity bill attached to that where if I had the hybrid solar I wouldn't. One of mine is a prefabricated container based unit, the other is a little Nyle L53. Both work well.
A lot of wood has been dried here with conventional kilns. The way to avoid excessive case hardening in thicker 3" lumber is to drive the heat into them at the start of the cycle... you need to get the core temperature of the wood raised before you start pulling moisture out or you are drying the heated exterior of the lumber before the interior has a chance to catch up to let the water move. A lot of case hardening can be solved with reconditioning also.
Why 8%? Thats a dry country spec, or are you thinking of exporting?
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