easy timing procedure Q

for initial startup I've always set the timing at 15 BTDC with a reluctor tooth even with the magnet tho with electronic dists from what I hear I will likely go 20 on my next one. I see UTG & power nation vids & they both say set the initial where you want it (one said 30 BTDC) & then twist the rotor to full advance & hold it there & at that point line up the magnet on your dist type & lock it down. what do you guys think? thank you for your time. RR