What is the average RoC at typical weights for the -200 and -300
As a rough guide:
-200:
1,500-2,000 ft/min at lower levels (below FL200), reducing to approx 1,000 ft/min at higher levels.
-300:
1,000-1,500 ft/min at lower levels, reducing to around 800 ft/min. The -300 can be a slug when climbing at higher levels, particularly when it's heavy. It can be a bit of a struggle to reach the cruising level prior to the FIR boundary ex HKG (eg. Envar or Dofin/Sikou)
Again, there can be a wide variation depending on weight/temperature, etc.