I live on about an acre in a township on sewer and water. My max outbuilding was 600sf. A former town board member and the building inspector were very blunt and upfront that the town board would NOT approve any kind of a variance for me for a larger building. Once they start to do variances like that for one, then they have to do them for everyone.
Then I read about another township about 20 miles away that had a property owner come to the board stating that this township's "accessory building" zoning code was behind the neighboring towns and villages. Board entertained increasing the size.
So I called my town supervisor. Explained the situation. He said mine was the 2nd request in a month he had. Encouraged me to come to the town planning committee meeting the following week. I did some research, discovered our town had the smallest max "accessory building" limits of the surrounding townships (they are six miles on a side in WI, 36 sq miles). Town board was very receptive. A couple supervisors said they had had comments similar to mine.
So town chairman directed town staff to review and come back next month. The zoning administrator did a nice job. I was there. My "angle" was that when the zoning law was last updated we lived in a different time. People have more "stuff" now. Boats, snowmobiles, ATVs, 3rd and 4th cars, lawn tractors, snow blowers, campers, race cars, collector cars, more toys.
I suggested they drive around in their respective areas and look at the number of cars, boats, snowmobile trailers, and stuff sitting outside. One supervisor said, "I don't need to drive around. I know LOTS of stuff sits outside."
I asked for an increase from 600sf to 1500sf on the lots 20,000sf to 1 acre (43,560sf). I would settle for 1,200sf. We stalled at 1,000sf and that is what they gave me. In retrospect, I think that if I would have provided some renderings of 1,500sf garages and shops and/or talked to them into a 42' or 44' max length facing the street ... I think I could have gotten 1,200 or maybe 1,500. I think they were afraid of 60x25 (1,500sf) detached garages.
Too many of the supervisors didn't want to double the size, just because it would be doubling. Even though town staff and the building inspector said that because of existing minimum setback, side yard, backyard, and distance from existing house ... that many of the lot/house configurations wouldn't allow more than 1,000 to 1,200sf in the first place! I got them to agree they would rather have a larger accessory building than "stuff" sitting outside.
My suggestion ... if you think the size restriction is too small ... contact your respective supervisor or trustee or alderperson and try to change the rule. Unless of course they say ... "Bring in a variance request, we'll probably ok it."
One thing to keep in mind ... say your zoning covers lots from 1/2 acre to 2 acres (based on the sf number you indicated in the OP, you're a touch over 2 acres) and you're at the large edge ... I think you're to have resistance because any change would impact everything down to 1/2 acre.
So look at the other zoning buckets. Lets say your town has 1/2 to 2 acres and then 2 acres to 4 acres (which is more liberal), then maybe all you need to ask for is a rezoning to the larger, more liberal zoning classification.
Another thing to be worried about ... having the largest lot in the neighborhood. If you have the largest lot in the neighborhood, that is a good reason for the municipality to not want to give you a large building.
Finally ... there is strength in numbers. If you find others in the community that want the rule changed, everyone who comes forward will help your cause. I would recommend talking to people in the community, builders, etc.
Good luck, keep us posted.