<font color="green"> Bob, I don't pretend to be an expert </font>
I don't either, but I do play one on TV /forums/images/graemlins/grin.gif But seriously, the reason that people like me ask people like you to fill out your profiles is so that we can learn where you are, what conditions you face in terms of soil, climate, etc. I always try to error on the side of caution, and I always stick with the recommendations of the manufacturers (both tractor & implement) because while both are "safe" both also recommend things that will allow their equipment to last a very long time.
As for some other things, let me see if I can help (and all this is coming from a city boy who moved out here about a decade ago and just loves to play with tractors). Gear machines typically will have about 1/2 to 1 more hp available at the PTO than a Hydro transmission will offer (in the size ranges we are discussing here). There is very little advantage to a gear machine for most "homeowner" applications other than the negligable bump in PTO hp and the cost savings when buying the machine. For both loader work and mowing (the 2 jobs typically that eat up most homeowner hours on a tractor and probably make up 80%+ of the total hours) are both accomplished faster with a HST transmission.
Do not ever make any comparisons between a garden tractor and a CUT. You will confuse yourself as they are mechanically so different that any comparison is futile. Sort of like comparing a Cat 3116 175hp diesel in a GMC 25,995 GVW commercial delivery truck to the 305 HO engine in my Avanti Convertible. By making a direct HP comparison, my Avanti should be able to pull one of my loaded trucks around backwards! The reality is quite different.
As for using a 30hp machine to mow, it is very common here! But I will say it is most common on a tractor like a Kubota
B2910 or
B7800. Those are fairly light machine and make great mowers, especially with a 72" mid mount mower deck. Those two Kubotas weigh only about 300# more than my 24hp New Holland TC24, if I recall the specs correctly.
<font color="blue"> In all honesty, when you start going to 30 HP tractors, the weight of the tractor itself would seem to make finish mowing kind of chancey, and defeat the purpose of buying one for using with the 72 inch deck. </font> There is often an issue of WEIGHT that comes up. I think it is fair to say that weight is only good if you need it, otherwise it is bad. And if that isn't confusing enough, then the real question is when do you need weight? Dealers (and even some manufacturer websites) say that heavy tractors are stronger, simply put there is no basis in fact for that statement on two similar size tractors. Further, some dealers/manufacturers condem tractors made on frames as being prone to breaking (again no basis in fact). If you are plowing a field then weight is good. Weight does equal traction. But if you are using a FEL, then BALLAST is good, but ballast is not weight. Ballast is counter-weight, or weight in the correct place. A heavy tractor is not a better tractor for FEL use IF the weight is in the front axel, engine, etc because that weight is forward of the "center of effort" of the FEL, therefore that weight simply does no good. Now if you shift that weight to the rear of the tractor, then that weight is good, but it simply is not enough. To safely operate any FEL on any brand of tractor of any size you need wheel weights, loaded rear wheels or a ballast box. Think of a schoolyard toy called a "see saw" or "teeter tauter" with 2 kids on it. If one kid is 50# and the other is 100# then the toy is unsafe. If both kids are the same weight, the toy is safe, that is how ballast works. Now, if you want to add weight to that the way some people argue that weight is good and light is bad, I suggest you have a 100# kid sit at the pivot point of that toy, and put one 50# kid on each end. . . the toy still works, while the overall weight is much greater, the added weight doesn't really make it work better or worse, it just exists. For doing some heavy digging into dirt piles, there is some advantage to added overall weight (remember physics class with the discussions on momentum & kenetic energy), but for 98% of the homeowner applications, that advantage is a minor one.