Not sure how Catachans play in 5th but we've done a lot of battles in 4th.
TLOS definitely changes things for the Catachans as they no longer have the "we shoot 12" and you shoot 6" " Big change there.
Running also means your opponent is going to close quicker.
Are you playing on Jungle boards, as per the codex? With Deathworld vets you are not going to going into tourneys. They need a special board set up to be effective (and fun!)
Take some booby traps. Your opponent will hate making difficult terrain rolls, especially with "move through cover". He'll have to make two of them the turn he charges.
Drop the melta guns for
AT. If you're playing, in the jungle, you're opponent probably won't bring tanks (maybe Walkers). It's a lot of dangerous terrain rolls for them to make. old rules had 6"
LOS so the big guns hardly got to fire, anyhow. Tyranids? Try demo charges, risky but powerful. You'll get more of them.
Stelek is right. Take the heavy flamers. You're units only get one shot and it's up close. Make it count.
The big trick, with the army, is to fight your opponent piece meal. You need to hammer on one part of the force while the rest of his force is making difficult terrain test trying to B line it for you and objectives. All the army except Ogryns get to infiltrate so you get to see where he is placed before you set up. Makes picking the weaker flank easier.
If you have a good gaming group you'll have a lot of fun with this army and jungle fights. I think you're opponent will dig it, so longs as he doesn't have too many tanks he is dying to use.
I run Orks for most of the jungle fights so I tend to bring lots of Stormboys, Dreads, and Burnas. Make for some great battles were you don't see the typical forces come out.
Also, I would recommend reading a couple Vietnam books. We Were Soldiers (Once and Young) is a great read. Effectively, two full day fire fights in landing zones. One goes well (relatively) and the other not. Saw the movie just recently and was disappointed with the length. So much goes on that couldn't be covered in a couple of hours. Tons of movies out there for reference on terrain, as well.
I can't wait to build that temple in "Apocalypse Now". Should make an excellent battleground for some cultist guard in the
WH book!
"The Horror..."
Let me know how it goes.
Cheers
