Congrats on the Explorer. It's always fun getting a boat.
I don't know about the advantages of bigger beams in your situation. I will comment on things I do know about after 40 years of trailering boats big & small.
1.) Listen to Parthery; He has a wealth of experience also.
2.) 7K is borderline for the weight of your boat & trailer. My 22 Seafarer & trailer weighed 5800 lbs, loaded & fueled, and yours will be heavier than that. It's always good to have some cushion for your trailer. That alone will save bearings, brakes, and other wear/tear items on your rig.
Borderline is bad. trust me, you'll hit bumps in the road, the boat will be flexing and/or bouncing up and down, putting pressure on the springs axles, etc. and over miles and time, you'll wear out the aforementioned bearings & other parts. I was putting in bearings once per season and sometimes more if I went a long way.
One extra thing here..If you just plan on pulling short distances back-and-forth to the local ramp, a 7K trailer should be fine. if you plan on going any significant distance, I would upgrade to a 10K trailer, 2 5000lb axles. I know, I didn't think I needed it either until I spent hundreds of dollars I shouldn't have on repairs. I learned the hard way.
Dealers, and sometimes individuals, will sell a boat/trailer package that is marginal for the boat to keep the price point down. They say, "You'll be fine, it's plenty of trailer." Maybe, if you just go a few miles per year. Again, I learned that more is always better.
3.) Parth is right about the 2-speed winch. It changed my life when I got my current 232 Gulfstream.
4.) Get trailer tires if not already equipped. Car tires do not have the inner sidewall strength of trailer tires. (Parthery and I had a talk on this; I still believe Goodyear Marathons are good, although there are other choices out there.)
5.) Consider a fresh water flush kit that employs clear tubing that gets freshwater to the axles & brakes via a garden hose hookup installed on the fender above the wheels. That is, if you boat in saltwater..
Luck to 'ya,