Oh I had so forgotten about that quote. Who in their right mind would transport bulk materials 300 light years?
SL is a whopping 400LY across with 1800 planets not even counting the Shell or protectorates. Your average bulk carrier is going to be the nearest system to a populated planet with an a steroid belt. Probably no more than 10 LY. Lets be UBER generous and round WAY UP and call it 30LY just in case most all stars in SL space are deficient in asteroids...
HV has fusion power and thus tranport of bulk materials will be at minimum half per capita what it is today. Oil/coal gonzos. Of course over half of earth's population hardly uses any coal/oil/LNG. All use products but they are produced locally.
As for delegate to population numbers, I have pegged each SL delegate equivalent to around 750,000 Million to 1.5Billion.
Intersteller transport I would peg at less than a quarter of what is transported per capita, as low as 5% per capita on earth today in HV in the SL proper. Shell and Verge per capita intersteller transport I would peg at less than 10% per capita and among the verge, less than 5% going to 0%.
WAG guess at number of actual transports should be less than 50,000. Of course if this is the case we have just as many warships in the HV as transports.
Now a tidy number of actual transports to Warships should be around 10:1 at minimum. Bit hard to categorize this on earth today, as there are lots of smaller transports along with plenty of small gunboats that are labeled as "ships" so go figure.
So, I have to conclude, that due to power of plot, the actual number of HV transports must be in excess of 200,000 and as many as 500,000.
Which brings up another conundrum. Where the heck are all of these transports built? Manticore built a large percentage. Does this mean 15%? 35%? To be a large percentage, I would bet on the 35% at minimum going towards 50%. If transports last over 100 years, that is still 2000-5000 built a year. This correlates to 700-2000 transports built each year in Manticoran space. Well, used to be built there anyways. Approx 1000 ships are built on earth today.