Newsflash: Property Assessment Board of Review Advice

I own a property in West Allis, WI. It is extremely unique. West Allis is a suburb of Milwaukee, WI with about 60k residents, and historically has among the lowest property value rates of any Milwaukee suburb. Five years ago, I bought a house that was likely one of the highest value properties for single-family residential properties in the city. It was much larger than nearly any other home in the city (4900 sq ft, 4 bed/3.5 bath) and all-brick construction. Someone had built a little manor in West Allis, where the average property size is more like 1500-2000 sq ft.This year we had a city-wide property appraisal. It hadn’t been done in 11 years, and my property hadn’t been reassessed in ten years. The average increase of property values was about 57% for residential properties, and about 48% when commercial properties were also included. (Manufacturing property values are set by the state in November.) My home was changed from around $400k in property value to $691k. The problem with my property is that there aren’t any comparable sales to it in the rest of the city given the size of the home.I’m not a huge person against paying taxes and I knew when I bought the place that I would likely have the highest single-family residence property tax bill in the city. It was 3x what we paid at the last place we owned (also in West Allis). Also, the largest single-family residential property sale I can find in the history of the city is from last November, for a home built in 2013 (almost 20 years newer than my home), with an in-law suite, a second kitchen, five bedrooms, etc., – it was $550k.I have a hearing with the Board of Review tomorrow at 11am CST. I have already put together and submitted my valuation process that I’m proposing to use. I guess I’m asking to see if this holds water in anyone’s opinion.What I did was find comparable properties in other communities nearby, other suburbs of Milwaukee, that do have homes my size. There’s quite a few – West Allis is one of the only cities around here that doesn’t have homes of this size. I took the last sales I could find (sometimes only one property of this size, sometimes 4-5) and averaged them to find the average sale price of homes of my size/bed/bath count in those other cities.Then, I found four nearby properties to mine that were smaller, about 3bed / 2bath and 1500-2500 sq ft. I averaged the sale price of those homes. I then found the last 6-7 properties of those sizes in the other communities where I had found comparable sales to my home and averaged those. Divide the ones in West Allis by the ones in the other communities and you have a ratio – a percentage, that you would apply to a home in those other communities if you picked them up and moved them near my home in West Allis.I then took those percentages for those communities and applied them to the average comparable home price in those communities to get what those homes might be worth if moved into West Allis, and averaged those prices. Came to about $540k, and this is what I put on the objection form.So….what do people think? Will this approach hold water? Is it too complex? I didn’t know how else to object in a quantitative manner… Opinions please!