Every time I do a yoyo - I find I have to gently jiggle the lines to tighten the wrap and control the kite.
The SF isn't the greatest kite to fly wrapped. That is just the way it is.
What do I need to refine to ensure I get a proper tight wrap so I can initiate multiwraps?
As long as the kite is level and you hit the stops, don't worry about how tight the wrap is. Don't let the kite lose momentum. Chris shows how it is done here http://vimeo.com/83173588
at around 1.10: large but precise slack-giving. Practicing multi-wraps is difficult because failure usually means a horrible tip-wrap super tangle: Zen-like tolerance of the walk-of-shame is helpful. As I am sure you've found out!