I'm sure there are plenty of experts who can give you way better advice here, all I can say is a little about dealing with a persian and a maine coon who weren't grooming fans. James (persian) had been badly abused before he was rescued, and loathed being groomed. Absolutely loathed. I did eventually find a plastic hairbrush that he liked the sensation of on his neck and shoulders, and I used that often as part of petting him, to try and get him to associate any brushing with not being a dreadful experience, and after a while I did manage to get a very quick brush of his tummy squeezed in between lots of head and shoulder brushing. Not at all the right equipment for a persian but at least something he'd tolerate. Done absolutely every day that helped to keep the tangles down, but every year when he lost his winter coat he matted. My local vets were great in helping with this and in the end we lion clipped him (under reversible sedation) about every 18 months, and then took him inbetween times to the nurses there in the very early stages of a problem when he was just starting to tangle, and they'd do a proper brush through under light tranquilisers, and clip any forming matts. They'd usually do this while I was there, and it took anything between five and twenty minutes, with him coming straight home afterwards. Using any sedation really wasn't ideal and not something I'd have chosen to do regularly without a real need, but James had been through a lot, he had a genuine problem with grooming and the priority with him was comfort and finding quick and low stress ways to manage his coat. The risks were better than having a seriously unhappy and matted cat, and matts can be very painful.
Mark (maine coon) didn't have a serious problem with grooming, he was just busy and didn't want to. I'd had him since a kitten so he was used to being groomed - he also had a habit of diving through the thickest undergrowth he could find and coming back COVERED in burrs, in need of immediate brushing, so it wasn't optional! With him I was gentle, interspersed grooming with petting and a lot of talking to him, but was firm and didn't let him get down until I was ready. (If he was really fed up I might only groom for a minute or two or less, but still let him go when I was ready rather than when he fussed, so he didn't associate fussing with getting out of it.) I groomed him in my lap rather than on a table, tended to put him on his back on my lap which made those long maine coon legs a bit easier to manage, and just was gently persistant. Mostly after a few minutes wriggling, he'd give up, co operate and start purring.
If you still have contact with your girl's breeder it might be worth asking her advice- most breeders with long hairs are expert groomers and can show you holds and positions for grooming that make it more comfortable and more effective for the cat- maine coons aren't the easiest cats to hold when they want out! They might also make some suggestions on things like baby powder, a little of which on easily matted areas like under the arms help stop tangles, but you only need a little and it's not good to use it too often as it can dry out the skin. If you have a good vets it might also be worth talking to the nurses there as they're usually very experienced in grooming, and see if they can help you work out some strategies.