Spleen - in my opinion you will be happy you chose Protech and hopefully you will enjoy diving with them as much as I do. Odds are they will sign you up for Turneffe but they will outsource it to Amigos Del Mar like most shops do as Amigos has the biggest boat.
Protech was working on getting a bigger boat for Turneffe trips but had not heard how that is going. As far as Glovers goes you need to stay further south for a day trip. Too far from San Pedro for a day trip. Also, check the diving links from the main page of this site for a link to Protech and an e-mail address. Safe Diving !