The Frontier series comes in 48, 54, 64 inch width and up. I have the SB1154 unit only because the wheel track is right at 48", too narrow in my opinion. 64" would seem to be too wide IF the snow were wet and heavy. So besides getting a get deal on a 54", it seemed like a good fit. Unfortunately this year we didn't have much snow to test my theory, but I doubt I will regret it anytime soon.
When I went shopping last fall, every sales person I talked to told me that the 54" was "ideal" for my 2032R. I wanted a 64". Every single one of them told me that I was pushing it and 64" was the absolute maximum I should consider. I ended up buying a 64" and it worked fine all winter.
On a 1025R, I'd think the 48" is the "normal" size most folks get but I'd think it could handle a 54" too. 60" is probably pushing to far.
I found a good deal on a leftover Frontier SB1164 and I bought it 2 winters ago. The JD sales brochures say a 54 is max but when you look at the specs the 64 is the same unit, just with a 10" wider auger. My salesman was in agreement that it would work fine on my 1025 and it does. I have no regrets in the purchase. The hydrostatic trans let's you easily control the feed rate w/o bogging the engine. And realize, if the snow is super dense and heavy the only full width pass that you have to take is the first one. The extra 5" on a side let's you get close to objects w/o the rest of the machine getting in the way and it makes the blower easier to see w/o turning around as far in the seat.
I would go with the 60". Look at it this way. You don't have to take full swipes with it if the snow is really heavy except for once.
I ran a 60" blower off a 25 hp Kubota and never had an issue with the tractor not being able to handle it and that was with a gear transmission and no live PTO so I only had one speed I could go with. A hydrostatic you should have zero issues since you have infinite speeds.
I don't know if they are just building tractors weaker these days or dealers have zero confidence in there products but it always seems they are way over cautious on what the tractor can do. I by no means beat the hell out of my equipment but I want to get every ounce of productivity out of it I can.
I'm using a 54" with my 1023E. I considered a 48" but was encouraged by the dealer to go with the 54. I'm glad I did, last year the snow fall was pretty light. However the year before we go a lot. I don't recall how much we got for the first blizzard but it was substantial! The tractor handled it just fine. If it were me, I'd go with a 54" if I had a 1025. I'm sure the 60" would be fine too. As others have said the first pass is the worst pass.