Oh my God, I don't know why but I thought that was hilarious Grasis...
"it's not as if you have extra eyesight stored in your foot" You really just made me smile, at how simple a statement that was, and how true. Love it.
Any who, now on to being serious, and actually answering your questions.
1- Really, this is a really vague bit Crpyt, and unlike many things like morphing or reimancy, its initiation is not explicitly stated. Which really means, it is within reason whatever you want it to be. As long as you either have a teacher who knows the skill and can show you, or have a book from which to learn it, and your way is reasonable, go for it.
So it can be done many ways, such as meditating and expanding your awareness, focusing on a rock until you finally see its aura... Or maybe even how I did it in
this thread. Or whatever is reasonable that you want to do. Within reason.
2- The flux at lower levels is only used to increase speed, toughness, or strength in the body, which is really helpful in combat.
Though bear in mind it puts a lot of strain on your body. Try to put to much strength into a limb, and you might just overexert it and snap your limb in half. Or blow it off, if a chunk of djed gets caught and builds up. And if you go to far, and lose control of your djed, pushing and overgiving to the extreme, you might blow your entire body apart, or pulp it as holes are blasted open from pent up djed trying to escape. Nasty, so best to be done with caution.
Flux- lore
The telltale sign is a painful, electric-like spasm coursing through the limbs at random. These lumps of uncontrollable energy travel all over the body, dealing damage from the inside whenever they burst or spike. The wizard is torn apart by his own life force, which breaks flesh and bone alike. Limbs pop out of their joints, at times even the eyes are ejected from their sockets.
-Now, if you are thinking of extending your 5 senses, you are better spent using auristics, not flux. Auristics can be used as an extension of your 5 senses, along with other things, allowing you to see and touch things by looking at its aura, without physically doing so, or even with your eyes closed. So really that cannot be done with Flux, but it can be with auristics. You might want to reread the auristics lore, under the part about
"Things that auras can tell". So dont try flowing djed to your eyeballs, unless you consider enhancing your senses blowing your eyeballs out of there sockets.
-And that last bit, about slowing your heartbeat, and such things, while possible, are only possible for MASTER fluxers. Look at the list of things that masters can do.
-Flux- lore
Again, the body is naturally fine-tuned to react in certain ways that are usually the most convenient, and overriding its workings should be done with great caution. Sometimes the Flux user seeks to take energy away rather than accumulate it: some masters were known to fall into self-induced comatose states, in which they could rest at a faster rate, by making energy flow out of their brain.
A master is a formidable machine that is only limited by his own body. Djed travels almost instantaneously and at will across his body, allowing devastating (if dangerous) discharges. He has mastered control over his internal organs and even bloodflow. His touch can cause alteration or disruption of another creature's own Djed Flux.
So a master fluxer could do those things, but try doing them at lower levels, and you will just end up stopping your heart, and killing yourself.