There is only one deck I think capable of running 70, the rest I stick to 64 or less. That deck is Guardians of Light. 6 draw creatures, 3 tutor creatures, 4 insanely good tutors. Imo, it runs BETTER at 70.
But if you go to 70 there are now 10 extra cards between you and the card draw. Even if you do get the draw, it now has to trigger an additional 10 times to get you to that card you need.
In fact, since you like using anecdotal evidence, allow me to attempt to use it against you here. I used to play Wizards' Star Wars TCG competitively back in the day, which was very similar to MTG in a lot of ways, including minimum deck size. For a while I got into the habit of building a 60 card deck and then throwing 1 extra card on top. Card draw was plentiful in that game -- really, really plentiful -- and like you I figured it would compensate for having an extra card.
Well, in one tournament I got through to the semi finals and lost the crucial game with that 61st card sitting quite uselessly in my hand. After the game ended I did my usual habit of checking my next 3 draws, and the very first one was a card that would have let me back into the game. If I'd been playing 60 cards I'd have drawn it and at the very least put up more of a fight, if not won. I nixed the 61-card habit then and there and have never looked back.
I can only say, try it again.
I'm serious. Make a GoL of at least 66 but no more than 70 cards and then play 2hg. I'm not saying this to be sarcastic, or obtuse or whatever, but for you to discover. Don't just throw cards in there though but put ones you want to play. At 70 cards, run 25 lands or, I promise you, you will get mana flooded. If you run 24, you'll get mana screwed. Yeah, that sounds weird, but it's true.
Since it's 2hg, try to team with someone with a lot of creatures you can enchant. That means no Dodge and Burn and no Mana Maze. Go light on creatures. Run 4 x kor, 2 x mesa, 2 x Totem Hartebeast, Dawn Elemental, and whatever else you prefer. Run as many enchants as you can 5 and under mana, but none above. Run all tutors. Run Retether. Focus on enchanting your opponent's creatures, they won't mind, I assure you,lol. Don't run many more creatures but the ones you do, focus on quality chumps as that's what they'll basically be.
If you have a steady partner, have them run Hunter's Strength and make sure they know to put Sacred Wolves in. I'm sure they'll know to put predator ooze in but many do not see the advantages to hexproof creatures like the wolves. I once had a serious argument with mjack over this. I ask you, friend, how can anyone not see the advantages to hexproof creatures?
You will find you'll speed through a lot of draw. I've milled myself down to 7 cards at times. When you have to discard, discard an enchant you don't need atm. You'll be setting up a retether win if it occurs. If you win with retether, unless you're the host or partnered with the host, don't be surprised if they kick you out of the lobby. It's happened to me so many times I've digital footprints on my ass.
You will find, if opponents are quality, that they know how to handle enchant decks but do NOT know how to handle the enchantment flood that you will unleash on them. That reminds me, spread the wealth in regards to the enchants. don't go for one super creature. Yeah, occasionally you can sneak one in but it's best to plan for more than that.
Be careful with Angelic Destiny now. Halo Hunters are now a staple in Lords of Darkness decks due to the influx of angels.
A spell often ignored but invaluable is Divine Favor. No, it's not the 3 hp it brings but the huge boost to defense for a cheap cost. On an early turn 3 sacred wolf, it makes up for the 1 toughness deficiency. For a kor, it auto turns it into a 3/7.
Learn not to enchant the mesa and you'll be surprised how it gets ignored while it's cranking out draw after draw.
Turn off simplified targeting. One very simple protection is to put pariah on an opposing creature, make sure it's one directly across from you, and then putting indestructibility on it. also,if vs illusions that are unprotected, your low mana enchants like Divine Favor become doom blades.
Give it a shot.
Edit: One important thing. You'll get called a lot of names at times so have a thick skin. When they do call you names, do me a favor and stretch the match out until they rage quit. I've been called every name in the book and then some.
ANd get used to them chalking up your victories as "luck".