Yes you could post to the For Sale Trade Forum. List the details; set is complete/set is incomplete and missing the folllowing card numbers along with the condition of the cards/set. Note any key condition issues epecially with key cards to a set, example, 93 Topps Gold Jeter, RC etc. Dont forget to mention shipping. Likewise look for comps on eBay so you are in the ballpark on price.
If you plan on using the site to trade you can also put a note on your profile page so people know that in addtion to your for sale trade you have the following sets/starter sets available for trade or purchase. They can message you and get additional details.
Regarding adding to your trade list. If you add to your trade list, it might be difficult to do if you already have cards from that set in there. Adding and removing those can be a hassle and once you post them in your trade list you might start getting trade request for cards in your sets.