"Supervision, micromanagement, these areas of economics are where we have flourished for decades. "
People did not even talk like that in Western Europe at this time, let alone Nepal.
Nepal's GDP in 1820 was approximately $1.541 billion 1990 USD, or £15 million in 1900 sterling. The 1815 pound sterling was worth around 72% of the 1900 one.
The general rate of growth was quite slow over the next century, doubling in 97 years. That could be increased, but not overnight.
Budgets/taxation for European states at this time were in the ~5-10% spending zone; Nepal would be limited to a much smaller fraction for quite some time, which is worth bearing in mind for planning purposes. There would be perhaps £500,000-700,000 every year to cover all expenses and costs.