I run two Different set up's in my trucks. The "little truck on 285's has a Toy rear and a Rover front. The rear is a Detroit the front is an ARB, 4.11 gears. Plus all the HD stuff.
I will trust this set up to 35's with moderate driving and figure it's a pretty balanced arrangment as far as strength goes.
The "big" truck has a 35 spline Salisbury and a Toy E Locker up front (with factory type voltages at the actuator) 4.11 gears it's on 35's,37's next with a gear change to at least 4.56's. I've never worried about stupid breakage on this car and the last damage was from me being stupid.
My 110's plan is Toy front and 35 spline Salisbury rear on 4.88's. with a 1:1 T case. Probably with ARB in the front, because I got a reasonable price on a new front third (open) and a Detroit in the rear.
The price of E Lockers can vary a lot, I've seen them for $350 to $1300, generally for the front used they go for about $450, Rears are usually a little cheaper.
My personal opinion is that the Toyota Mini Truck Diff is what the Rover needed in the first place, I've done my Rant on this over and over so it's moot to start another argument. Leave it that In the rear (unless it's a Series) I will never leave a Rover diff in a Rover that I intend to off road (that means lower gears) regardless of tire size. In the front I may leave the Rover diff, the available HD components are usually strong enough for most moderate wheeling applications and even some crazy stuff if the driver has Skilz.