Basically:

1) If the continuous contract is acceptable for backtesting, just use t6 files with a single asset list line. (No contract interface needed).
2) If I must backtest on a contract-by-contract basis, either use t8 (CONTRACT) files or one t6 of the underlying VIX index and live-load t8 datasets, all using a single asset list line. (Use the contract interface.)
3) If I want to trade live, I would need the contract interface regardless to load contract info. This would require a single asset list line.

I do not recommend having an asset list entry for every futures contract, it's not as good as using the contract interface. But if you did want to do this, just use t6 for each contract.