Sorry for the delay, somehow missed this post.
Larger injectors and ecm programming would be the first choice.
I dont remember which engine your using, but some Toyota enthusiasts have had the intake manifild/plenum machined to accept an additional injector, a lot like shooting in a wet nitrous charge.
On my Supercharged 99 3.4 I've machined the plenum to accept 3 new injectors, which are mfgrd by Bosche and controlled by a Bosche stand alone system capable of controling up to 16 individually operated injectors, The system allows for individual sequencing and flow control rates.
For my system the added injectors are each dedicated, one for adding larger fuel volume to cylinders, one for alcohol as a faster burning fuel catalyst, and one for water to cool egt.