1. You can click on the small layout plot to enlarge it, and still vary the primary baffle tube length with the slider to see the effects on primary obscuration due to either the primary or secondary baffles. You can also click the "Optimize" button to calculate the baffle geometry that gives the minimal central obscuration. Clicking on the plot again shrinks it back to original size.
2. You can also click on the spot diagram plot to enlarge it, and vary all the spot diagram parameters in large mode. Click again, and it shrinks back to original size.
3. I think I have gotten the utility to store CD2 Cassegrain designs in OSLO-EDU format working properly. Due to its 10-surface limit, OSLO-EDU can't draw the baffles like CD2 and Zemax, but the imagery can still be fully analyzed in OSLO-EDU. CD2 and OSLO-EDU layout plots and spots appear to agree very well.
As ever, give this a try and post up any bugs. CD2 is an after-hours hobby I can't spend a lot of time on, but I'll try to get to it when I can.