OK. How much space do troops (being transported only) take?
Lets take a BattleDress Company. Minimum Kit for a several month sojourn in one or more theatres. Must take all required personal and equipment to operate alone, on in coordination with other forces. Does not require Food and Fuel, carried in additonal cargo space or sourced elsewhere.
5 platoons of 25 men, all in battledress.
Command and Control (25 men)
Sensor and Communication (20 men)
Medical and Maintenance (30 men)
This is a little skimpy on support personel, but I am assuming that there are mechanics and medics scattered in the platoons, and the extra are the specialist mechanics and medical personel.
I am assuming a model of a set of multipurpose battledress, everyone in the company is issued a suit, and the personel who need the armor least are the first to be cannibalised to keep the core force in working order.
I will assume that there are 200 emergency low berths for carrying personel. There would be a handfull of people that would not be low berthed in most situations (CMO,CTO,CEO + support), but I will leave space for them anyway.
I am assuming a large (30dTon == 42,000 vl vehicle ) command vehicle/vehicles. Similar sized medical and repair bay vehicles, effectively mobile hospital and mobile repair base. Additional 30dTon in transport (Ambulance /retreival/repair) vehicles and sensor/comm vehicles.
So
200 Emergency Low Berths 50dTon
200 350vl BattleDress units 50dTon
Mobile Tactical Command 30dTon
Mobile Hospital 30dTon
Mobile Repair Base 30dTon
Recovery/Sensor/Comm Vehicles 30dTon
Total 220 dTon
So you can fit one of these companies in a mercenary cruiser (The modular cutters have to have two of the Mobile bases in them), with a very small ammount of spare space for fuel and food
You can approximately triple the number of troops if you make them all footsloggers (less need for repair, no need for battledress space). A mechanised infantry company (smaller organisational design) would take about the same space. Armored companies would depend on the size of the tanks.
With minimum life support you are looking at 1 soldier per 1 ton, though you can try to push that up to 1.5 soldiers per ton. Any more then this and you start to no longer have sufficient life support, which might be OK for a one week jump, but I wouldn't like to convince a company that this was a good idea for multiple weeks. This is balanced against 4 soldiers per ton in compact/risky low berths, without no where near the same cost in life support supplies. Keeping your soldiers in cargo for the company outlined above would take an extra 150dTons of life support (for multiple jump engagements) or an extra 75 dTon or so if it was definitely only a week.
Returning breifly to topic, the number of ships troops on any ship is purely dependant on the situation at hand. A naval vessel doing active boarding is going to have all possible troops on board, possible even breaching the 3/100 dTon suggested upper limit. The same naval vessel doing ranged interdiction will have less troops on board. A pirate vessel will have whatever is appropriate for their method of hunting. So it comes down to their is no meaningful way to give a statistic for "number of troops carried" though their does need to be a stat for "minimum crew" and "maximum personel (crew+passengers)" which gives you an idea of how many troops can be carried on board at a pinch.
Apologies for rambling.