You can't actually "sharpen" a reel mower without both a reel grinder and a bedknife sharpener. Each piece is several thousand and are made by Neary, Ideal, or Foley. That said, you can backlap the reel to the bedknife. Requires grinding compound such as Clover, and usually a bell crank to reverse rotation of the reel. You need to gradually adjust the reel into the bedknife as you backlap, until you have contact across the full with of each blade in the reel. Then, after cleaning up all abrasive, you need to adjust the reel relative to the bedknife so that you are just shy of contact, and check at several points on each blade, so that it is cutting like a pair of scissors. Don't know how your mower adjusts. On professional Trimmers and Tru-Cuts, the reel rotates in eccentric bearing housings, camming in or out relative to the bedknife. On the cheaper Trimmer Homeowner, the McLane reel mowers, and the old King O'Lawns, the reel is fixed and the bedknife adjusts in and out relative to the reel. If it sounds complicated, it is to a degree, and also very time consuming. Takes a pro an hour or more, which usually means a bill of $75 to $100.

Think of it as improving the gene pool! :-o Seriously, you do have to wonder about the survival instinct of a creature that will not get away from a power mower. Frankly, as much as I am a fan of reel mowers in the right circumstances, it apparently won't make much of a difference here. You won't mow any slower with a reel mower, so if the critters are not getting an early-warning signal from a noisy power mower, they aren't going to fare much better with an almost-silent reel mower. Maybe the one benefit I can think of is that the reel mower will stop as soon as I do, so you buy yourself maybe a foot or foot-and-a-half (in distance, not on the critter :-o ) of stopping space. Would that would be enough? As for impact on allergies and asthma, I don't know as a reel mower would be significantly better than a power mower with a bag -- except that you won't have to deal with gasoline odors (if you're sensitive to those). In fact, since reel mowers usually cut a narrower path than power mowers, you might find you're outside longer than you used to be. If grasses and the like are your allergic trigger, that may not be a good thing. But at least you won't be swirling around a small cloud of grass/weeds/dust out the open chute of a power mower.

First lets talk reel and bedknife. Sounds like you need the reel adjusted to the bedknife (or cutting bar). The reel & bedknife work like a scissors to cut the grass. There should be minimal but consistent contact all along each reel blade and the bedknife at all positions. Basically the reel just "kisses" the bedknife. The reel is adjusted by loosening the bearing holders on each side of the reel. The rear bolt on each bearing holder is a fixed point and the forward bolt can travel through a slotted arc, which brings that end of the reel closer to or further from the bedknife. Make sure you scratch witness marks on the sideframes around the bearing holder before you loosen anything so you can return to the original setting. The reel is checked by taking strips of paper (about 1" x 4") and checking the cutting action of each reel blade against five or six points along the bedknife. If you are not cutting, CAREFULLY adjust that end of the reel closer by gradually moving the bearing holder. I use a drift punch and a small hammer. Check and recheck, and then finally tighten all bolts to lock things down. If this doesn't get the reel where you want it, the next step is to backlap the reel using Clover Compound. This is an abrasive grit suspended in grease. A layer of compound is spread in the cutting area of the reel, the reel is brought closer to bedknife, and the reel is rotated backward to grind or lap the high spots off for better reel to knife alignment. Repeat and recheck. After cleaning off all the compound, then set the reel using the procedure in the about paragraph. Still not good enough? Now you need to have the reel and bedknife professionally sharpened. A reel sharpener is basically a lathe with a power grinding wheel on the tool post, traversing back and forth. After a shop grinds the reel, they will then backlap reel & knife to clean up the last few thou, and then set the reel using the paper strip method. Figure $75 for a backlapping and $125 to $150 for a full sharpening. As for cutting height, you said you were already at highest in front. This means you have already pulled out the cross rod for the front wheels and placed the rod in the lowest of the three holes in the sideframes? As for the rear wheels, adjustment is similar, but much more time consume. It's been my experience that usually adjustment of the rear wheel high is rarely require, as long as you are already in the middle position. BTW, for years McLane had no rear wheel adjustment. The rear mainshaft (which the wheels rode on) had its bearings pressed directly in the sideframes.

The 17" is a completely different design. Among other things, the drive mechanism is a "mickey mouse" friction drive to the rear wheels, similar to that used in some cheap front wheel drive rotary mowers. Also, it uses a special engine with an extra 1/2 speed camshaft drive. Nothing inherently wrong with the engine, but if you have to replace the motor, your choices are considerably limited. The 20" and 25" are similar designs, both a lower cost knock off of the Trimmer. McLane uses belt drive to the mainshaft and a different reel and bedknife arrangement, but otherwise shares the roller propulsion drive and other features of the Trimmer.