UPDATE: as suggested, I split this question into separate parts (links below). I left the last one here. It is so silly I am rather proud of it ;)
UPDATE 2: it seems that breaking one post into multiple questions only annoyed people, which wasn't my intention. Please, accept my apologies for the spam.
Over past few weeks I've been reading LT datasheets and application notes and everything I googled on the web. While I think I am getting the basics right, some rather unexpected questions popped up and I could not find definite answer to them. I'd appreciate any help or even a point to the reading material I could use, something like "flyback for dummies" would be the best :)
Calculating minimum primary turns - Answered
Wire selection - Answered
DZ snubber - Answered
Final question, if the load draws pulsed power and output caps are sufficiently big can I use average load current for the purpose of DC-DC calculations?
For example if output is modulated at 50% duty, can I use 1/2 of its current as secondary coil current?