PowerBuilder to Adobe Flex

I want to convert PowerBuilder to Flex. I have 6 .dlls that are no bigger than 3756kb each compiled in PowerBuilder. No real graphics, entry type screens for business where the back end is driven by COBOL/Oracle so the screens are really just display shells for the back end engine. Maybe 15 screens plus the same number of popup type screens inside them. I keep reading about others having problems with SWF file sizes, mostly with pictures/graphics. So…

  1. What can be expected in the above scenario, size - wise?
  2. What type of memory, class, browser minimums will be needed?
  3. Any problems with 30 users on at a time?

I am thinking for a non graphical app that we will be OK but I need some info above.

Thanks for any wisdom you can provide me.