Re: What size brush hog??
I have the same 48" mower as smittydog, a Land Pride RCR1548, also recommended by my dealer. My BX2360 handles it easily. The dealer recommended it over the 42" mower because the blade tip speed is higher and you'll get a better cut.
I also mow on slopes and added 2" wheel spacers and filled the tires. This was also recommended by the dealer and I never tried it without the spacers/water, but it has proven to be very stable. Still, work the slopes up and down, instead of cross-slope, as much as possible.