New to Zoho & lot of questions

New to Zoho & lot of questions

Before I start sorry for my English, I'm spanish spoken.

This is the scenario:

I just started my own business a few months ago managing corporate aircraft. I have more than 12 years of experience in the industry. 

I developed a MS Access database for this purpose and is working really good, the problem is, as everybody knows, sharing and collaboration.

The application has more than 80 related tables for different tasks (flight planning, flight scheduling, aircraft and crew logbooks, passenger information and documents, flight expenses, crew funds for expenses, maintenance, reports with a lot of queries, ect.). There are at least 60 access forms and more than 30 reports from more than 90 queries.

After viewing a lot of Zoho reviews I think it will help me with all this business tasks and specially for sharing statistical information with aircraft owners and collaboration with crewmembers and accounting departments.

This is the question: Which will be the best approach or workflow to start designing such app?

One of the tables that I use for querying purposes is the Airport Table that has more than 20,000 records with airport codes, coordinates, city, state, country, etc. Does I have to import all those records? Or can be fetched as a spreadsheet?

I know VBA is not supported in Zoho, but I can use Deluge Script and SQL for queries. What about customs Functions? One of the functions that I have in my Access App is to calculate distance between airports (Great Circle distance formula) and flight time depending on the type of aircraft for that specific leg.

I need some advice about this project please to see if it is possible in Zoho and which other Zoho products will be suitable for this.

Thankyou in Advance.
Jaime Cuellar
Monterrey, Mexico