My thoughts:
Probably lumber and dairy should have variable tariffs on them.
Dimensioned, kiln-dried softwood lumber tariffs would be based on wholesale per board foot prices received by four leading US mills during two months not more than five months past.
Conifer plywood tariffs would be based on wholesale square foot prices received by four leading US mills during two months not more than five months past.
The dairy tariff might vary based on Canadian region (British Columbia, Alberta-Manitoba, Ontario, Quebec, eastern provinces) and be based on three to ten large regional dairy farmer received prices for milk (by hundredweight and cooperative dairy profit sharing by hundred weight) on a monthly expectation schedule adjusted by the Canadian CPI.
A modest tariff for reduced Canadian drug prices would be imposed by the US. The drug pricing tariff is to make for a level playing field for American businesses.
The Canadians might be allowed to export listed amounts of various things tariff free except for the drug pricing tariff in exchange for importing a comparably valued amount of US goods of listed types.
The Canadians would draw up their list first. This might be past yearly amounts in dollars adjusted by American CPI inflation and by 3% per year to adjust for population growth.
The American negotiators would then match by value (and American-set sectoral percentages thereof), largely based on historical exports to Canada.
If there is a shortfall in Canadian imports of US goods, including dairy, compared to Canadian exports of Canadian goods, the US could respond as per the agreement, typically by say imposing tariffs of 20% of the sum of the total amount of the import shortfall plus 10% of the sectoral import shortfalls as the Congress, the President, the Secretary of Commerce may decide. The President would decide when each measuring period starts and ends, the default being close of business the last day of December.
If Canada imports more than the listed amounts of US goods, the Canadians could export more listed goods to the US tariff free except for the drug pricing and lumber tariffs.
In all cases, Canadian basic (unalloyed) aluminum would come in tariff free. Each buyer of it might be required to buy US aluminum in a proportion the President may decide from time to time, and by US time zone, to keep US aluminum producers in business.
Canadian petroleum products would come in tariff free if the WTI intermediate price is above $60/barrel adjusted by the US CPI from the December 2025 amounts. If the WTI intermediate price is less, then a tariff no greater than the percentage shortfall may be levied as the Congress, the President, the Secretary of Commerce may decide.
Canadian exports, except for drugs needing FDA labeling, need only be labeled to meet the statutory requirements generally applicable to Ontario or Quebec. US exports need only be labeled to meet the requirements the statutory requirements generally applicable in three states having Republican governors.
The Canadians might be allowed to export listed amounts of manufactured products tariff free except for the drug pricing tariff in exchange for importing a comparably valued amount of manufactured products of listed types.
Raw materials such as ore, unalloyed base metals (iron, copper, aluminum, nickel, etc.), and crude oil would not have to be listed or matched.
Canadian petroleum products would come in tariff free if the WTI price is above $60/barrel adjusted by the US CPI from the December 2025 amounts. If the WTI price is less, then a tariff no greater than the percentage shortfall may be levied as the Congress, the President, the Secretary of Commerce may decide.