Mom & Mother-in-law Personalities Clashing!

You should both have a talk with your respective mothers about how you want the planning process to go. It's great that they want to contribute financially, however, this wedding is between you and your FW, not you, your FW, and both of your moms. One resolution would be to have each parent agree to cover certain vendors, so there's no compromising between the two about budget for certain things. You could also just ask them each how much they feel comfortable contributing total and use that money how you see fit. I personally would tell them that I appreciate their offer to help, but I would rather plan and pay for my own wedding instead of having a wedding that someone else wants me to have.

If they aren't each giving you cash that you are then free to choose how you spend it, are they willing to allot their contribution toward specific items (especially your mom)? Like, is your mom more comfortable knowing whatever her, very generous, contribution is, is going toward things she considers "necessities," like food, beverage, your dress, DJ, etc.? If so, work with her on how she wants to apply "her contribution" to those items (e.g., does she want to write checks directly to the vendor or give you the money to pay for certain things), and assure her that once "her money" is spent you are fully aware that's all she can contribute, so you and FW and/or FMIL will cover everything else. And, again, you are so thankful for her contribution!

For daughter's wedding, FOB and I initially contributed about 75% and FOG contributed 25%. FOG had VERY strong feelings about the professional photography, so the cost of that came directly out of his 25%. Beyond that, he didn't really care how D & SIL spent the remainder of his contribution, which he gave them in cash, but once it was spent/allocated, that was it. I worked much more closely with daughter regarding the choices she was making, and over time it became clear there were things that she'd really like to upgrade/add that weren't part of the original budget. FOB and I agreed to cover those increased costs, and ultimately, we paid about 80% of the total cost and FOG's contribution covered about 20% of the final budget. We ALL (including SIL's mom, who is divorced from his dad, and wasn't able to contribute anything financially) "hosted" the wedding, regardless of the cost/contribution breakdown.

Good luck!

I agree, the best way is to divide and conquer! Each mom has some control over some things, not all of it!