No one has answered this yet, but his question was the Nautical Mile Range of a Seafarer.
Assuming he chooses 50 miles as his safe trip range, the Nautical Mile Equivalent is 43.4.
I use statute miles too, but I thought I'd answer the question as written.
Couple notes on the area your boating in:
Many is the day in the summer months that you'll have light NE E to SE breezes in the morning when you go out and a localized seabreeze in the afternoon on your way back in. This translates to a following sea going out and an onshore following sea coming back in. I have a great friend whom I grouper fish with sometimes, and he's seen that happen dozens of times.
During winter when the cold fronts punch all the way thru, things get a bit more cantankerous, but you'll still have your days. SE to SW winds will precede an incoming front and when the boundary passes, they will veer NW and then NE for 2-3 days post-passage. Most of the time they are 15kts or higher with 2-3 footers common, unless the Hi pressure pushing down is weak. Afterword, it'll lay down 'till the next front comes thru.
Venice Inlet, as you know, is a deep and easy passage. (Don't get too close to either jetty bank or you may get a fishing line in your prop.) Stump Pass and Little Gasparilla Pass to the South are iffy at best. Shoaling occurs and the depths & channels are always changing. Navigate them with local knowledge gained, or be very cautious with your hand on the trim button all the way in. Same with Big Sarasota Pass to the North, although the Sarasota Yacht Club has updated nav info on Big Pass. The latest channel is marked with floating ATON's that the Yacht Club members move according to the shifting sands. Check their website for the latest.
This info is purely subjective. I had a Seafarer for 10 years and loved every minute. My comfortable limit was and is 10 kts and 2 ft seas. I am speaking of the wind chop that is common in the Gulf. Rarely do we have the swell that LuckyDude experiences on a regular basis. Occasionally, we'll get long period swell sprung from a distant storm, like Laura a few days ago. Mostly the Gulf just bounces you around, and 2 footers are my limit. Yours may be more. The boat can take it., although when it stops being fun, I go in.
Keep us updated on the boat, your Fun Factor and where you go.