Upgrading B&L Stereozoom 4

[Dale]

Currently using the B&L Stereozoom 4, with 10 15, and 20X eyepieces, a 2X aux lens, and a variety stage attachments. What make and model
scope would be an improvement? I don't use the higher magnification very often. The loss of WD with the aux is a pain.
A boom arm is very appealing, but the good glass comes first. (my Nikon has spoiled me)
I would consider just a head as I have a complete inverted microscope stand that I could jimmy it on. A quick scan
of Ebay brought out these:
1. Zeiss DR $600
2. Olympus SZ3060 $470
3. Olympus SZ61 $840
4. Olympus SZ4045ESD $580
I am still searching the forums. Dumb question, but is the Greenbaugh type obsolete? If I can't spend more should I
quit?
Dale