meizzwang

These points have already been mentioned, but here's some more insight:
1) deleafing the lower leaves on younger, smaller plants when relying on rain for water might actually increase the growth rate only because more water will get into the root zone. Since those lower leaves are older, they're not as active in capturing PAR, so it might not negatively affect the plants.
2) Chopping off newer leaves may cost you on yield.
2) Getting the plants to produce as many leaves as possible in the quickest way possible is likely the way to induce flowering the quickest.
3) That pH issue has to be resolved if you want maximum growth. Cutting the grass was a good move, but it may not be enough to lower the pH significantly.
4) while adding significant organic matter to the soil can initially be costly and labor intensive (probably not an issue in Thailand though), fruit quality may increase, so you can possibly demand a higher price per pound on the harvest. It'll also probably buffer the soil's pH for much longer periods of time compared to sulfur, which likely requires multiple applications.

One test that I'd like to see is if having the ratio of nitrogen slightly lower than P and K on bananas. Higher nitrogen in other plants tends to delay flowering, while stressing N and increasing P and K induces flowering earlier. Timing of nitrogen stressing might also play a huge role: is it better to stress younger plants, and then increase N near the flowering stage, or vice versa? Or does it have no effect on flowering time?