1. It's "Trackman Time" head out to your local golf store who has a Trackman and spend an hour in their testing area.
They should or may have new or used Covent drivers on hand to demo. Speak with the sales guy and inform him you have a slower swing speed and like the Covent driver. He most likely will recommend a 10.5 loft with either a R - flex or the senior version which is generally a lighter gram shaft. Both products should produce a higher launch and greater control, but you may sacrifice a few yards in distance capabilities. If your typical ball flight is very high, you could try a 9.5 loft and play with tee height and ball position to accomplish a desired flight with either loft club.
2. EBay is a good place to shop for pricing, but a local golf shop sometimes may be a better deal if they include re-shafting.
Some of the newer blades have some help built into them. The iBlades do for sure, but I think if you want help built in then you'll have to go with cast options instead of forged. I have to say though, you'd be hard pressed to tell the difference between a forged blade and the iBlade when it comes to "feel" and sound.
Driver does seem inadequate since it's got a big head on it but a 3 iron for those who carry would do just fine I imagine. Better yet, just get a cattle prod. It can fit in the bag and doesn't count against you as a club. A lil ol zap to the zipper fly area ought to adjust a persons attitude right quick.
Where is the hole in your game? Do you struggle close to the green? Then look at lob wedge. If you find yourself always needing a 200 yard club then go for a wood or driving iron.
I would suggest since you already mentioned you don't hit your hybrid so well replacing it as well. I don't hit hybrids myself, but there are many different types of hybrids from fat sole driving irons to short shaft woods. A true hybrid will go a lot farther than an iron of the same loft making a 5 hybrid get into you 3 iron range. If you go this route I would suggest a 2 and 4 hybrid to cover the gap between driver and irons.
My personal preference is toward big fairway woods. Most people will carry at least a 3 wood. Lots of pros are using a strong 3 wood, whether it is called a 2 wood, 3+, or mini driver, these guys are using 11 to 14 degree woods with lots of club head speed to get 300 yards out of their fairway wood. But with slower swings that most amateurs have they should be using a 12 to 14 degree driver meaning they should be using more loft on their fairway wood as well. To go this route you might want to look at a 4 wood and 7 wood setup. A 7 wood should be around the same yardage as a 3 hybrid.
One last suggestion. Find a 2nd hand store and look at some older model clubs. You might just run across a 1 iron for less than $10. For that price you could grab a hand full of long irons, hybrids, and woods that you can then hit the driving range and find what works for you.
So IMO, if there are easier options to hit that can produce similar results, why play blades?
I had a set of Titleist 710 Cavity Backs and sold them for blades. Simply because they looked cool, and "all good golfers play blades". Well, I wasnt as good a ball striker that I thought I was. I now play AP2's and my handicap is as low as its ever been. For guys like Jordan Spieth and Luke Donald in your example, if they hit it pure most of the time, why risk that 1% where you dont pure it and the blade iron leaves you 15 yards short of your target and in a creek/hazard.
The technology in irons today is incredible for hitting high shots while still being able to work the ball plenty. Im not knocking anyone who plays blades, because that is impressive. It all comes down to preference.