I don't have a slingshot bag, though they sound a great idea. Wouldn't have thought they could be any worse than the rucksack type bag that you either lay in the mud to open, or your kit comes tumbling out while you try and balance holding it. 

Tripods - so much depends on what use you want to put it to. Hope you're fit if you intend to carry the 475B  very far, with that head it is 5.7Kg. Add that to the weight of camera and lenses and it is quite a lot to carry. 
Personally I prefer a lighter tripod and head - use your camera bag as extra ballast hung from the tripod if it is very windy.  I use the 190proX and 460MG head, you could upgrade that to a 055ProX if you need extra height.

The choice on type of head depends what you are used to, and which you find easiest to use. I have never got on very well with ball heads, find them very difficult to position, I prefer a three way head simply for ease of use.  Others have no trouble and prefer the ball head.

And every one said, 'If we only live,
We too will go to sea in a Sieve,---
To the hills of the Chankly Bore!'
Far and few, far and few, Are the lands where the Jumblies live;
Their heads are green, and their hands are blue, And they went to sea in a Sieve.

Edward Lear
http://www.nonsenselit.org/Lear/ns/jumblies.html