Not much happening offshore in May except for Striped Marlin , jacks, perhaps the odd sail, dorado and tuna. Even inshore is fairly calm in the offseason, but you can check "hot bites fish reports" for the year round Mexico fish reports as I may be a little fuzzy.
http://www.mexfish.com/mfn/mfn2006/m.../mfn060508.htm
Josh has a Capt named Lora on a 30' Grady. He will be about $900 a day, excellent inshore and offshore.
Josh at Ptime Time Advebtures usually gets $1200 offshore on the Grady and up to $2000 a day on his Cabo if he captains, which is worth it if you want a +200 lb yft of 500 lb marlin Sept-October.
www.primetimeadv.com
Even the inshore Panga charges $600.
Capt Danny Osuna or his brothers are also very good on the Marla 1, 2 or Arca de Noe at $650 offshore and they have refurbished these older boats.