Not everyone holds from the Sheitel. That is optional depending on what your family normally does. It is usually FLOP or 50/50 or whatever the two mechutanim decide on. If you decide on 50/50 you talk about the expenses beforehand. You don’t say 50/50 the sky is the limit. The point of 50/50 is to stay within a budget. You make decisions together and so you both have a say in what is chosen and organized for the wedding. If one side likes a more fancy wedding then you are better off sticking to FLOP and letting each side do what they want or saying “I am willing to spend “$X” for the wedding. If you want to spend more that is up to you but this is all I can afford to do. I would prefer to do it together so we both know what the other is doing, but if you want to go FLOP we will handle our responsibilities and you can handle yours.”
The most important thing is NOT to get the kids involved int he financials. And if you are the kids you should know that it is NOT your business and YOU should stay out of it. Don’t be the messengers and don’t be in the middle. If they try to tell you what’s going on or complain say “that’s not my business, that’s between you and my parents or between you and my future in-laws”. Don’t get in the middle because that will cause machlokes between the chasson and Kallah.