I'm Skimchee (name still in the process of being changed on Smashboards). Yeah, I use the SHFF method because it has pretty much no commitment. It doesn't charge as quickly as if you stand still and hold B, but it is definitely safe and keeps your Ivy mobile. Seems like it also has high priority because I actually started using it to break the D-air pressure in the Mario matches (wish I found out sooner though). Hopefully I'll be back this Tuesday to show some other techniques I've been messing with :D
EDIT: Make sure you pay close attention to your charge light, it's easy to fire a solar beam prematurely when you are using this method.
EDIT #2: Bad news. I can't make it to Xanadu due to some errands that I need to complete before I head back to college. However, I plan on getting a capture card to post friendlies and junk, so I will hopefully be able to start contributing more Ivy to the thread within the next few weeks or so. Live long and Solar Beam!