Zero turn - effort required steering wheel vs lap bar. Also suggestions for bad back

Okay, so here's my situation. My home sits on a 1.25 acre lot, mostly level with about 600 ft long x 10 ft wide drainage sections of maybe 10 to 15° max slope - corner lot drainage along streets. It's not very smooth, and if not for weeds, I probably wouldn't have what passes for a lawn About 3/4 of it is clear flat mowing, the other 1/4 has the 20 trees, small drainage slopes, etc. There is 800 ft of level fence (both sides require mowing). I'm currently mowing it with an old 38" Yard Machines rider that has seen better days (I'll probably keep it for a back-up or to mow the slope if needed). It currently takes me over 2 1/2 hours just to mow, plus 1 hour more for trimming by hand mower and weed whacker. I'd really like to knock an hour off of this weekly chore.

I am so confused though as to what might work best, given some medical issues - and the over abundance of ZT choices out there. My medical situation is three ailing lumbar and one neck vertebrae that can get pretty sore from all the bumps, plus shoulder and neck issues that are worsened by the repetitive turning of the steering wheel. There are lots of obstacles on the property, so I have to make a lot of tight turns which aggravates shoulders/neck pain.

So many questions...:

How much effort and how much travel is required to turn the wheel on steering on the steering wheel ZT's?

Would the lap bar type steering require less effort and motion and be less aggravating to shoulders (my initial reaction is lap bars would be less strain)?

How much would a ZT with suspension, such as Ferris 400s help, or going to an entry level commercial machine like a Gravely ZT HD 48 help?

Given the size of the lot, I am balancing the cost of a higher end entry level commercial machine. Currently have looked at Ferris 400S and Gravely ZT HD 48, both roughly $4500 + out the door, vs a $3000 Toro SW 4200 steering wheel type, vs $2400 Toro SS 4225 lap bar type.

Would the higher $ machines be all that much faster given the obstacles? It's too easy to fall in love with more expensive equipment than one really needs, and I wonder if the SS 4225 with a nice extra seat cushion or an upgraded seat would save me some serious $$$, get the job done just fine, and not aggravate pain.

Thanks in advance for your thoughts.

A stander will be kinder to your back than a sit down machine,
If you go for a sit down fit the optional suspension seat
Go for the smallest deck you can get they are much easier to navigate around tight spaces.
Big decks are at the best advantage when you can do lots of open wide runs on flat ground.
The bigger the deck the more they tilt and scalp when mowing rough ground & turning.

ZTR's are balanced a lot lighter on the front than tractor type mowers so always require less effort to steer.
Some lap bars are adjustable under the deck to reduce the sensativity of the bars, usually only on commercials.
A couple of my commercial customers have them adjusted so the travel full forward to full reverse is about 10".
They drive with 1 hand holding both bars.
The other hand can be used to weed spray along the fence lines ( requires you to always have the fence / wall on the left ).
We put a shelf over the top of the engine with a 5 gallon powered sprayer. That saves a lot of time