If not cutting grass you could weld a pair of high lift blades for each spindle at 90 degrees of each other. Welding would insure the blades stay at 90 degrees and not slip. Noting blades with stars would need blade's star removed. That would be the blade farthermost from the spindle mount. This should double the lift and exit pressures. Now gator blades would be a better choice as you need to reduce the leaf sizes making easier to blow out.
Any combination should work. 2 hi lift, 1 hi lift and 1 Gator, or 2 Gators. Some Honda walk behinds already have Ninja blades which are double tip blades. Just note you can't run these blades for cutting grass as it would too much of load for the engine; unless, a higher HP engine is installed. Either it is going to cost more than $30 for a complete set.
Example would be my 42" MTD mower where I went 16.5 hp to 21 hp. There was one drawback in doing this as I was burning up the deck belt and had to upgrade the 1/2" belt to a 5/8" belt but now I can cut 12"+ heavy grass without a problem. Just have slow a little to allow the deck to clear the cuttings. Before I had crawl at the lowest speed to even 6" over grown grass.