My advice is simple: everyone besides L200 should only finish normal. Instead of continually asking for information, why don't you contribute?
It's a work in progress...honestly, most of the normal rewards are terrible...levels 12-14 are 3k-5k units. First 15 levels of heroic are even worse - 100-200 units.
Normal (15 levels):
8/15 - 8 units, 121 Hp, 24xp - 27xp (Redrock Frogman 665/589)
9/15 - 10 units, 119 Hp, 27xp - 30xp (Baby Whoo Bear 836/905)
10/15 - 'Boss' unit, ? HP, 30xp - 33xp (Pathmaker 1,377/1,038)
11/15 - 7 units, 270 HP, 32xp - 36xp (Frozen Viking 1,746/1,612)
12/15 - (Polar Piggy 2144/2517)
13/15 - (Polar Wolf 3301/3172)
14/15 - (Young Hailstone Golem 5217/3777)
15/15 - Apprentice Alchemist (6869/5620), Magic
Heroic (25 levels):
4/25: 13 units @ 13xp/hit - 18xp (Young Fey Creep 131/107)
5/25: 5 units @ 16xp/hit - 21xp (Blight-Rider 164/119)
6/25 - 1 unit @ 19xp/hit - 24xp (Mineralist 150/184)
7/25 - 13 units @ 22xp/hit - 27xp (Walker of the Pass 199/198)
8/25 - 6 units @ 25xp/hit - 30xp (Redrock Frog Warrior 276/200)
9/25 - 14 units @ 28xp/hit - 33xp (Papa Whoo Bear 295/272)
10/25 - 1 unit @ 31xp/hit - 36xp (Pass Digger 404/270)
11/25 - 7 units @ 34xp/hit - 39xp (Frostbite Viking 447/352)
14/25 - 2 units 43xp/hit. - 48xp (Hailstone Golem 809/540)
17/25 - 9 units 52xp/hit - 57xp (Burz Mabus 1207/1071)
18/25 - 36 units 55xp/hit - 60xp (Snaga 1355/1354)
22/25 - 58 units 67xp/hit with 125hp and 225 energy/strike (Marsh Plagued Mechanism 2723/2723)
23/25 - 29 units 70xp/hit with 285hp and 235 energy/strike (Creature of Black Marsh 2982/3501)
24/25 - 12 units 73xp/hit with ~750hp and 245 energy/strike (Gripping Vines 10142/6762)
25/25 - 10 units ??xp/hit with 1078hp (Master Alchemist 56667/46363 - no bonus attached)
Info courtesy of BG and Shelob for 22-25H.
Thanks everyone for helping.