I'll give you my personal opinion on this. For me, more important that the knot itself is to know the propper way of making it fast, easy and reliable.
Chose a connection knot that you feel confortable with and then tie it again and again and again till you feel absolutly sure of it, till you can make it under any circumstances well and even with very few light.
Be sure to dominate it, and use a know taht is easty for you. Many knots work well so you should have no problem.
Other thing I'll tell you, I don't use large top shots with spectra and I use equal or heavie mono top shot line that the GSP line, for 30 pound GSP I'll use 30, 40 or 50 pound mono, never less that the resitance of the GSP. I'll always use a Biminni on the GSP to make a duble linea before making a connection know with GSP line and I try to keep things as simple as possible.
But then again, that's my personal approach, try your's.
Jan, Do you fish shorter topshots for halibut? My butt setup is 65lb Power Pro or Toughline W/10' of 50lb mono for a topshot. Almost no stretch even when fishing 600'+ and the mono breaks before the Spectra so I'm not leaving prop seal eaters floating around the ocean.
the man on the beach knot, (Brandon heywood. WON ) THE RODDY HAYES KNOT. tie overhand knot with spectra on to mono. (Leave about 15 inches tail of spectra. Tie up a n improved clinch not , worm wrap away from overhand knot around the mono toward the hook end (away from reel) make 15 wraps give or take a few, then wrap back down intertwine wraps evenly, pull through the first loose wrap. cinch down. blame heywood when it fails, it's not his invention either !!