Just humble opinions on what little I know. Hope it helps.
1. I don't have any experience with hydros yet, my new x500 will get its first workout tomorrow. I suspect there is a limit to the weight it would pull up a hill and it won't go anymore. I went bigger for the same concern you have, but also wanted to be able to use a sleeve hitch plow or box blade in the future.
2. I think all JD baggers come with high lift blades to help with the bagging. At least that was the case with the bagger on my old 160.
3. Ride comfort. I haven't learned yet about relationships of overall wheel diameter to hydro performance. On a gear differential taller tires will feel more sluggish and shorter ones more torquey. I'd think there is a similar relationship with a hydro, but don't know to what degree since there is no ratio to play with.

I think you need a ground-engaging Sears DSG6500 for all that tugging and pulling weight. Skip the lawn tractors and look at real garden tractors. Either the Sears or something in the shaft drive CC 2500 series. With all due respect to Deere, the X300 is NOT the same tractor as the CC 2500 series as the latter is shaft drive and ground engaging.For that matter the X300 is not the DSG 6500 either,

Might want to look at the Simplicity tractors if there's a dealer anywhere near you. Talk to the dealer and tell him what you want it to do and see what his recomendations are. Spending a little more now might actually save you money in the long run because of it lasting a lot longer.

Thanks for the input. My first tractor was a Sears (made by Roper). It was about 5 years old when I bought it in 1983. A couple years later something broke. I checked the manual, went to the local Sears w/ part number in hand and they told me to forget it. It was over 5 years old and they had no availability for parts. Ever since then I've been wary of Sears.

Their current line is mady by Husqvarna. Until last year, Husqvarna used the 510 and the 3000 hydros from Hydro-gear. In mid 2006 they switched to the K46 for almost every tractor. If I knew the Sears 6500 had a better tranny I'd certanily give it a look - I suppose 20 years is long enough to hold a grudge:-)

I looked at Simplicity but the closest dealer is quite a distance.

The Craftsman 6500 series continues to use the Hydro-gear 3000 series tranny. 469 ft/lbs intermittent torque, 260 ft/lbs continuous. K-46 tranny, 243 ft/lbs intermittent, 187 ft/lbs continuous.

What is a "10% hill"? A hill with a 45 degree angle is a hill with 100% slope. So I see your hill as 10% of 45 degrees, or 4.5 degrees. That's not too much slope to require 4WD. So to better understand your "hill" let's use a clock. With the hour hand on 9 and the minute hand on twelve, move the minute hand until you reach the angle that you see your "hill". So where between 12 and 3 does the minute hand point? At 9:15 level terrain is achieved accross both hands. My apologies if this sounds odd to you, but I see so many references to "my hill" and "yard slope" and "degrees of yard". that I can't help but wonder if we are talking the same number, percentage, or degrees. I use the clock because I think most people have one versus a protractor or a compound mitre angle finder. Thanks!

My suggestion would be to look at the Simplicity Conquest. It has a K66 tranny. Should be enough for what you need. It also has a differential lock that may come in handy at times.

I would take the ride to the Simplicity dealer - you may find it worth it.

Enjoy the journey.

eal51 in western CT

A 10% hill is a 10% grade.

rise/run*100%

10 foot rise over 100 foot run = 10% grade or about 5.7 degrees

Look at Kubota too. The T-series are nice mowers...I have one.

I don't know if your truely need a 4wd for your hill. My old propert had some severe slopes and I always did it with a 2wd. My Yardsman handled most of it with ease. A couple spots you didn't want to get into though. My Simlplicity Conquest could get into all the places. he locking differential was really handy. I'd suggest getting soething with a locking differential for your slope. The issue with going to 4wd is it cuts down on manuevabilty. For the most part, they just don't turn as sharp. So unless you see yourself getting a garden tractor with some ground engaging attachments, i really don't see the need for the 4wd.

The conquest is a better choice since it has a better hydro... If you keep that tractor 15 years or better the engine generally will survive with any decent care. The one expensive part that might make your ownership experience bad is a hydro that fails... Getting a better hydro now and changing fluid and filter on it every five or six years should insure a better long term ownership.