I have a feeling that small cargo ships are more effective than large ones

-reasoning: Large cargo ships have a much larger capacity, the equivalent of five small ones, making them cheaper on gas and otherwise more "efficient" on resources, however, after the impulse upgrade for small cargo ships, the comparative speed is laughable. large cargo's combustion engines make them a perfect anchor for your ships (only a ten percent increase per tech); slowing ur entire fleet down to the same slow speeds. small cargo ships, which have the same base speed as bc's and bs's, have a much more effective technology behind them (20% per tech on impulse); allowing your fleet to travel at maximum speeds, whether it is for raiding other planets or moving your own resources. so, the real questions are as fallows- when you can make tens of thousands of ships, is that extra gas money really that important? and when sent on a raid, does a small cargo ship's performance lack when compared to large cargo ships? (do they survive as well?)
please share your thoughts, all of the above is pure theory (I don't want to sink money into a fleet of small cargo ships to see it crash on the first raid, lol)