Start familarizing yourself with the limiters that will hold you back. To add fuel there is only so far you can go without manipulating tables. The ecm can only go to 120mm3 of fuel, so you have to work with what you have to push more fuel than what the tables are written for(you have to modify the pulse tables to add fuel). You'll also want to download a copy of a timing calculator and learn how to use it. Duramaxdiesels.com has most all the calculators you'll need if you search through there forum. 50% is a good starting point, but you have to balance timing vs cylinder pressure as well as egt's vs ect's all the while making sure not to make it sound like a rattle can of spray paint. For lmm some things are straight forward to shut off, while others do not respond correctly. Go slow and small with your changes, and if you decide to go big, be ready to buy an engine because you can crack a piston real quick in an lmm. Also don't forget to check your modifiers as lmm's are loaded with them. I used to post up tunes until I found out somebody I was helping for free was using me to fix tunes for his customers he screwed up, so I normally don't even give out pointers anymore(just lost the taste for it after I got used, then found out people were taking tunes I built, and selling them as there own). Lmm tuning is not one to really cut your teeth runing on, took me quite awhile to make heads or tails of them, and I wasn't new to tuning by any means. Go slow, make small changes, log your changes, but I also like to add in visual checks as well.
