Hi Skfir,
I'm just an ordinary soul, and glad to hear that you're moving your blind-assist device along to its final form. When it's all working it would be fun to see it in action! PCB layout can make or break a product. It's actually something I rarely do because where I work there's an engineer who does it so much better than me. Generally in PCB layout the value of resistors, etc. is not especially important -- you can (and probably will!) change a few in the debug process. Far more critical is the layout itself -- pin-outs (3-terminal devices are a real pain!), trace runs & grounding of high-frequency portions, etc. These are messy to fix in debug.
Bob