Understanding gas & L1 DA costs

Hi, have a few questions to help me understand fees on Fuel:

  1. I see opcodes have their associated gas costs resulting from benchmarks fuel-vm/default_gas_costs.rs at master · FuelLabs/fuel-vm · GitHub – are these opcode costs generally accurate or can I expect these to change very dramatically soon? (Asking because last time I dug into gas, it was before any benchmarking was done and I was told to ignore gas for the time being)

  2. How does the fee structure work, specifically wrt the DA costs of writing to Ethereum L1? Optimism and Arbitrum take very different approaches to how to cover both L2 costs and L1 DA costs. For example, the gas limit on Optimism just considers the gas costs from L2 gas usage, whereas on Arbitrum their fancy 2d fee model means the gas limit of a tx includes L2 and L1 costs and therefore changes a lot with L1 gas price fluctuations. How does Fuel charge both L2 and L1 fees?

  3. Generally, do the same concepts from the Ethereum gas world translate? E.g. some intrinsic gas for each tx, gas cost per byte of calldata in the tx, the gas limit must cover these intrinsic & calldata costs as well as L2 opcode costs, single gas price that generally doesn’t depend on what the tx does (i.e. no fancy gas pricing for high demand state like Solana), etc?