As Droshi says, it's all about experience.
As someone who only started freehand sharpening about 9 months ago, the lessons I learnt are:
I would be careful with natural oils like nut oils. I believe they can go rancid when put into a board. Although generally I don't care much for mineral
If you want a true foundation book, I don't know of any better than 'La Varenne Practique' by Anne Willan.
How would you use a 4 sided strop ?, as in what combination of pastes, I guess !?
Could you use a combination of strops in lieu of stones
I really love my 270mm Gengetsu. It's a stainless clad White #2. I had originally planned to get the semi-stainless, but it ended up being out of stock