>>127649
Aw hell yeah, a fellow OpenTTD player. I'm a casual player myself but I personally use a combination of strategies A and B for my networks
Basically you have several larger networks that are (practically) disconnected from each other, and then I add more lanes to those individual networks as the need for upgrades arises. This usually works well for my needs since I never have more than 10 to 15 trains on a network at a time, but your mileage may vary. ┐(ﾟ～ﾟ)┌

As for your issue, there IS actually a mysterious third option: [OVERFLOWS]
Overflows let you quantum-stack practically infinite amounts of trains at every dispensing station with minimal strain on your infrastructure budget. They do require very specific station setups to make them work, but unless you like building really large or really small stations it shouldn't cause too much of a problem. Additionally, you'll need to use a LOT of signals to make this work. The trains need to know if there's enough space for them to leave their storage closet and without proper signalling this kind of setup can clog up relatively easily (especially once you start having more trains waiting in depots than traveling on your network. Thank God you don't pay maintenance fees when trains are in depots). As for how to actually build them, well, I did say I was a casual didn't I ? Thankfully there's a lot of guides out there that explain it a lot better than I ever could