Should have mentioned that my intent is to use DDM (ProShare Ultra Dow) for any 2X exposure requirements, but to keep exposure to that at a minimum.
If therefore Ladder currently indicated 100% exposure I'd have 100% invested in 1X (conventional) holdings.
If the exposure indicator then rose to 120% I'd sell off 20% of 1X holdings in order to purchase 20% of DDM (80% in 1X and 20% in 2X for 120% overall exposure).
If later the indicated exposure declined back down to 110% I'd sell off 10% of DDM and replace that with 1X holdings (90% in 1X and 10% in 2X for 110% overall exposure).