I wonder if this would work:

Small player: 10.000 NW and 2,000,000 rp on construct

Big banker who wants to do a funny investment sents over 108 Mill gc to the small player.

Small player queues at 86.4% construct:
Tick 1: 20k soldiers - cost 1.07 Mill GC
Tick 2:  2 Mill soldiers - cost 107 Mill GC

At tick 3 the 20k soldiers come in. Your construct would drop to 33,3%,  at this point the 2 Mill soldiers are worth 150 Mill GC.  Canceling the built returns 75% which equals 112 Mill gc.

Net gain: 112M - 107M - 1.07M= 3.93 Mill gc in 3 ticks.

Basically you can compare it with 1% interest per tick,   while it would otherwise decay at 0.5%. It would be risky though Miss out on a tick and exit gc.