OK, so reporting back... I told my SN pro to load 50,000 asteroids on startup.
When I restarted it I reckon it took about 10mins to start! But once it was going it was fine. The program basically seemed dead but it came good after 10mins or so. When they were all loaded pretty much everywhere you looked there was several asteroids
I've put mine back to 5000 and will only up the load amount when I need them.
My mac also has 8gb of ram (Mac Pro 8core). So maybe David you just need to leave the program go a bit longer.
I don't think my machine would handle 100,000 very well though, let alone the 500 od thousand in the database
Dave.