Excellent idea for the reference targets Max. The subtle curve on the saucer is going to throw in a little monkey wrench, but nothing that can't be overcome. Taping on a temporary reference guide might be a good idea. I'm kind of thinking back to the optical illusions Steve was seeing with his half scale saucer (it was so big that the eye couldn't quite process all the straight lines with the curves). At the very least, I am filing that idea away for future use.
Concerning the question of "accuracy" to the "studio model" technically any TOS Enterprise model kit is going to be an idealization in some fashion (and I think this was addressed in either the first or second 1701 club update). The 11 footer was unfinished on one side and had some asymetrical details. The ole three footer was a complete model, but rather different proportionally in several areas (sort of like the differences between the 5 foot Millennium Falcon from ANH and the 32" model built for ESB). The rest is down to lighting, special effects, some trick photography (reversing of shots), and other things to make a hand built 11 foot model look like a starship. But, while it is the Enterprise on TV, the model is no more the Enterprise than William Shatner is Captain Kirk. Is he Captain Kirk? Yes. Does he have the combination of the safe in his quarters committed to memory, I doubt it. So is it the Enterprise? No, but it plays one on TV (not trying to be snarky here, just interjecting a little humor into the mix).
So, it is a judgement call as to what to do on the model (do you mirror image the left side for the right, or do you keep some of the asymetries on the windows?). Do you go all smooth, or do you go with some raised relief in spots? How do you replicate the raised pattern on the impulse engine deck when originally it seemed to be a cloth overlay? Do you go with an open shuttle bay? If so, how do you do it when the real miniature set has a bit of a TARDIS effect in there? It is always going to be a judgement call. Cost is another factor. Ideally, we want a company to make something "right" if they can. But there is always going to come a time when the decision has to be made that enough has been done since the company doing the model doesn't have unlimited funds and customers who might buy it don't have unlimited pocketbooks. Plus, there are also customers who will say "I want it now, warts and all". So, which group do you appeal to? A company has to try and find a happy medium for all three factors. Otherwise, the model kit could become a financial disaster, no matter HOW good it is.
When we build the model, it will also be a judgement call on what things we want to do. Do we light or not? Do we go clean or weathered? What brands of paint do we use? Do we use decals or try to paint stuff on? So, every model of the Enterprise done from this kit is going to be ever so slightly different depending on the skill of the modeler and the choices made. That doesn't mean the models will be inaccurate necessarily because each person will have their own choice to decide how to make the model.
In my case, I want to model to get me the 95 odd percent of the way there and I can use my own model skill or judgement to overcome what is left. Besides, are we modelers or just mere kit assemblers? On the RPF, I would say most of us are "modelers". But just remember there has to be a certain amount of work done for the "kit assemblers" who might not have as much skill or time. The grid is a perfectly good compromise to me. Besides, it is A LOT easier to fill a grid and make a model look smooth than it is to scribe one in my experience. So I think the "To grid or not... to grid. THAT is the question" back and fourth is overblown.
I know, we all have different opinions. That is what makes us human. But in determining whether or not I am going to plunk down three bills on a 1/350 TOS E, an etched grid is FAR down low on the list of things that would make me consider not buying it. When the only alternatives are expensive pre-painted replicas (some being better than others) or resin kits (some better than others), styrene is more appealing at least to me. After sanding off enough raised saucer grids on 18" AMT Es and scribing in lower rings on those saucers, filling grid lines on a 1/350 model (if I should choose to) is a thing that doesn't require that much effort. But of course, I am a unique individual and my skillset is going to be different from others.