You may want to consider a monthly subscription to ExpertFlyer to check upgrade availability for your proposed flight. From coach to business, you are looking for "C" class availability. Well worth the $5 to see if you can find a flight you can immediately upgrade right after purchase.
https://www.expertflyer.com/frequent-flyer-programs
If no availability exists, you will be waitlisted and, as mentioned above, with no status you are near the bottom of the list when they are processed.