I can almost kill him, I get the fat cunt down to a few juts left and he does his double attack thing which wipes out my health.
Bah you bunch of pansies.
I've done O&S Solo, first time because my Xbox wasn't connected to the internet and I ran out of humanity and the second time, because I wanted to man-mode them at Soul Level 1, at that level you simply can't summon for help apart from Solaire and as much as I love the sunbro, I wanted to up my game. On both runs I also did the supposed 'hardmode' version (Giant Ornstein) but I consider Giant Orns easier than Giant Smough because apart from his lightning ass slam and his ranged attacks, all his attacks are purely physical (the first time through was with a fat rolling strength weapon using heavy armoured mofo using the Greatshield of Artorias).
Trust me Mr Bear, the fight can be done, what is required is patience. The first time through with that fight solo, it took me 30 minutes to do, you strike only when you can be sure you can get a hit in without getting blindsided by one of them. Ornstein is easier to take out first because he is more mobile, thus tends to close the distance a lot quicker than Smough.
If you don't have the DLC O&S are THE hardest fight in the game, the only true bosses that are harder are in the DLC (Though for my money the hardest fight in the game isn't strictly a boss fight but the Dual Sanctuary Guardians, imagine O&S only both can fly, is ridiculously fast and has ranged attacks, oh and they love to blindside you...still never beaten those two bastards).
I would suggest leaving out Solaire for the fight, summon real players, you can buy a single humanity from the shopkeeper at the shortcut between Firelink Shrine and The Depths or since the bosses are still standing, simply grind them OR place you summon sign down near the bonfire and get summoned for O&S to help other players.
I don't have the personality for this game, it makes me far too angry.