Yeah, man!
Glad to see that you've got an instructor that:
1. Supplies gear.
2. Isn't following the hype that's plainly market-oriented and not diving-oriented.
He's right about the fins. "Testing" by various entities (all of them paid for by fin manufacturers, regardless of whether they tell you that or not) shows that splits are simultaneously faster and require less effort. Whether this is true or not (I don't believe so, based on my experience), seasoned divers rarely list "speed" as a desireable characteristic of a fin. Diving isn't about getting around as fast as possible, and even if it was, speed has a direct correlation with thrust - so the more water you can move with your fins, the faster you'll go. If you look at the dynamics of a propeller in the water (what the splits are supposed to emulate), there is no likeness whatsoever to split fins - it's all marketing hype, plain and simple. If splits did what they advertise they do, then boat propellers would be soft, flexible, and split down the middle.
What IS important to seasoned divers when it comes to fins is:
1. A good fit. This can be achieved through the use of the right bootie between the fin and your foot. Every person is different, and every fin is different.
2. Preciseness of control. With a short, stiff fin, it's much easier to control the fin tips of the fin than it is with a long, floppy fin. Control of the fin tips is the key to a variety of different fin kicks, including the much-talked-about "backward kick." Short, stiff fins are easier to keep off of the coral, work much better in confined environments (like shipwrecks and caves), and are easier to control so that you don't kick your buddy. "Big floppies" fail miserably in all of those departments.
3. Negatively bouyant. Plastic fins float, which means you'll have to compensate with more lead on your belt - and then tend to be "feet floaty." A negatively-bouyant fin will leave you with amazing control of your trim with the bend of a leg, negate the need for ankle weights, and actually allow you to take a bit of lead off of your belt.
4. Stiff enough to allow you to put whatever power you have in your legs into the water. Remember, fin propulsion is all about moving water... Historically, "jointed" fins and plastic fins fold up easily, "slipping" in the water and robbing you of propulsion. Because you're a big guy like me, I would definitely recommend staying away from plastic fins, jointed fins, and splits.
5. Durability. Plastic scratches easily and looks worn quickly. Cheap plastic fins will fade, too. Solid rubber fins tend to stay nice for a long period of time, and if they ever get worn-looking, a shot of Armor-All (or spray silicone) will make them look new again.
For these reasons, I wouldn't recommend the Tusas that you pictured above... Plainly, you're "overkicking" them anyway, and need a stiffer fin in order to get your power into the water.
My favorite fins - and therefore my recommendation to you - is a set of ScubaPro Jet fins, like these:
You may find a problem with the foot pocket of them, though... The size XL will probably be too small for your foot, and the size XXL will probably be too big. You'll have to test them out to know for sure, with a variety of booties to find the right mix.
If you DO find that neither of the ScubaPro Jet sizes fit your foot, then look at a set of IDI Turtle Fins, which are essentially the same fin as the ScubaPro Jets but with a foot pocket halfway in size between the XL ScubaPro Jet and the XXL ScubaPro Jet:
Either way, I do NOT recommend purchasing a set of fins without first trying them on. This may require you to do a little driving to make the right choice.
...And when you purchase the fins, try them on with the bootie you've got and leave yourself open to purchasing a new bootie that works better for your fins.
...Since your instructor is a ScubaPro dealer, has he not suggested a set of Jets for you?
And yes, I DO recommend replacing the rubber strap with spring heels. Aside from being uber-cool looking, they're functionally amazing, and solve all sorts of problems. I recommend the ones made by Halcyon - simple, high in quality, and installed in Halcyon shops on-the-spot so you don't have to.
Hope that helps.
Stay away from flimsy plastic fins. They're made for children and little women who aren't going to overkick them.
And no, the new Tusas won't dive any different than the old ones you're diving now. They may look terrible as they get old, but no, they don't "wear out."
Hope that helps.