Is it legal to use dungeon finder (texture pack) ??

You are a true pirate and not like those idlers who get experiences and iron out of nowhere then. *Highfive*

Well, I do have grinders, but I go out and mine my ores and stuff.

That's good as long as you don't sit for hours collecting xp without moving a finger.

Either way you have to move a finger... Unless you use a script(which is banned I believe) you do have to kill the mobs in some way. So not as many fingers, but it's hard to do it without moving a finger.

Yeah like many have been saying, F3, torches on one side, minimaps, mining above layer 12, and digging down it a 2x1 tunnel while holding shift are all things to do that will make the game much easier on you. I tell, when I started Minecraft I had my share of deaths while mining( just ask Pab hehe), but now I'm proud to say the last time I died on this server was about a 2 months ago trying to pick up a item in the ocean... Which I soon realized was a bad idea. After awhile you just kinda get a knack for remember little tricks or things and you know where and how to look for things.

No, you aren't alone. But there are some tricks that will help you. Work your way down to level 12 and mine in straight lines. Don't push right up against the blocks you are mining. Carry a bucket of water and place it above any lava you see. Most of the time, the tops of lava pools will be at level 12 or below, so they will not flow onto a block you're on. If you happen to mine into flowing lava, you can step back and place water or another block to stop the flow and then mine in a different direction. Bring a ton of torches and food. When you get to an abandoned mine or cavern, place torches there but beware of mobs--especially creepers. At level 12, sometimes rare(r) ores are visible in abandoned mines/caverns without even digging, but there will be monsters there until you get everything lit up. On the other hand, continuing to just dig straight ahead through solid ground and placing torches about every 10 blocks will make it so you never see a mob.

On your way back home, stay in a boat most of the time, and you'll never see a mob then either.

There's almost no difference...

And what do I do if I have a serious lack of luck?

The Macro mod lets you macro the process of switching texture packs so example To switch to x-ray pack you could press K and to switch to default you could press L or any button.

No offense intended, but I find that most people make their own luck one way or the other.

No, although I think a mod is allowed to see what kind of mob spawns on the block you are standing on.