It was calculated a while ago that the following combines are the optimal way to get to a 1k shard as fast as possible with the lowest use of shard/shard binding agent ratio.
So you still have to use shard binding agents in some of the following steps:
2 * 280 = 319
4 * 319 = 443
4 * 443 = 615
4 * 615 = 850
2 * 850 = 1k
How many 706's do you need to get to 1k+? 3 or 4?
When combining shards is there any trick to getting more DMG for a combine or is it all a base increase for each combine.