This freaking process is unbelievable… The utility won't give us an estimate on running new gas and electric without plans drawn up by a licensed architect, the architect can't do the drawings without knowing which service(s) each piece of equipment will use, and I can't make an educated decision on that without knowing what it will cost to run the services.
It's a good thing I don't have to worry about losing my hair over this…
IME, the utility shouldn't need drawings but they will need load calcs and/or a list of your equipment. We typically start out with what we want and if the cost of service is too much, we back down from there. I'm generally dealing with electric service, but I believe the same iterative process works with gas service. What you intend to use will drive the size of the service. On bigger buildings, that may change the entry point for the gas or water line depending on which adjacent street has the main that can provide the size of service we need.
Regardless, you should give the architect your ideal list of equipment. He can calculate the gas service you need and/or pass that list on to the utility to do so. The utility can tell you if what you need is available at that location. If not, or if too expensive, alter your plans.
My final piece of advice on utilities, based on experience, is that ideally you want to stay within the parameters of the service that they already have available. Second best is to stay within what they are REQUIRED to provide to new users. Sometimes existing facilities don't match current requirements.
If they need to bring new service it is #1 expensive and #2 puts you at the mercy of their scheduling. Utilities are not known for keeping to schedule nor for staying within budget.