...
"intensity" : "d,1,18",
...
on the line: "intensity" : "d,1,18",
doesn't that assume 3 cards? Also, I just tested on my config and d, at least for BTC mining stands for Desktop if I remember correctly, si I think it adjusts difficulty as necessary to be more accommodating of other things, but it doesn't disable the GPU, if that's the intention (sorry, didn't read the thread on the other forum.
For example, an intensity of d on my machine did change the I to 7 from what normally would be 9.
Hope this helps, at least a bit...
Edited to add:
Found this in the Mining forum "LTC Mining links":
CGMINER GPU FPGA overc monit fanspd RPC stratum linux/windws/osx/mip/r-pi 2.11.4
https://bitcointalksearch.org/topic/official-cgminer-mining-software-thread-for-linuxwinosxmipsarmr-pi-4110-28402
If you are unfamiliar with setting up the configuration file (using tag / flag settings to connect to pool or settings etc) you can use this
[Application] cgEasy v1.0.1--Generate CGminer config for LTC Mining easy!
http://forum.litecoin.net/index.php?topic=36.0
haven't tired this CGEasy config maker for LTC mining, but it might be worth checking out too.