Indexes in a big table. (About 400 mil of rows)
Since you are optimizing for reads you could simply add one optimal index per query. So if your query is

select price_per_unit from Sales where exclude = 0 and partner = 42


Create the index (exclude, partner) include (price_per_unit).

You say that writes and disk spaces are not of significant concern. So add the optimal indexes to support your reads.