Hi Rob,
I've never had any weed catch the running line loop. I cut the tag close (always leave about 1mm) when I have pulled the knot tight. With the varivas stuff it's best to pull as tight as is needed to close up the knot and not pull as tight as possible. Check for any stress marks once knot has been tightened and re tie if there is any stressing to the main line. Fairly strong stuff that takes a perfection loop well, I've only snapped it and lost a head once and that was fishing 35lb fluoro. This was not through choice I picked up 35lb instead of 25lb, only other thing I had was 15lb which would not have carried the tubes I was using!
A loop to loop is less bulky going through the guides that an albright IMO and you will usually never have it inside the guides when casting and shooting so should not be an issue. Only time you'll notice it is playing a fish but again, it is smoother than a braided loop to polyleader for me.
Cheers
Ben