Stu there are hundreds of thousands of Toyota pickup trucks out there with the same basic radial ball bearings as your "green" bearings and they live long tortured lives for over 100K.
The first question I ask when setting up a rear is what kind of axle bearings are you going to use? Rollers get the spacer and ball bearings do not.
I would really call the expert Cass (doctordiff) for your options on tapered roller bearings if you don't want to disassemble your differential. There may be a bearing retainer that you can shim like a Ford pickup uses to adjust the axle endplay.

Gus