Does the size of the cap booster affect the shield boost bonus

It depends what area of the game interests you most.

You can certainly become a trader, miner or manufacturer on your own, however I think the game comes into it's own when you're part of a larger entity where your contribution really matters.

In terms of planetary stuff, have a look here: http://wiki.eveuniversity.org/w/index.php?title=Planetary_Commodities I'm up to tier 2, and could get to tier 3 on my own, but the trick is to find the right commodity to invest your time in. (as always).

Planetary manufacturing is almost solely single player at the moment as you cannot set up automatic manufacturing between different players at the moment.

The stacking penalty applies to the bonus, not to the module.

If you have a thermal hardener and an EM hardener fitted, both would provide the full resist bonus. If you add omni-resist plating, its thermal and EM bonuses would be reduced because of the stacking penalty, but its explosive and kinetic bonuses would not.

The precise formula is somewhat complicated, but it can be summarized as:

1. The first module provides 100% of its bonus.
2. The second provides ~87% of its bonus.
3. The third provides ~57% of its bonus.
4. The fourth provides ~28% of its bonus.
5. The fifth ensures your fit gets posted in a "fail fits" thread on the forums.

The order you fit the modules doesn't matter; the one with the largest bonus will always be considered "first".

Some modules (notably Damage Control Units) are exempt from stacking penalties.