Ah hah, I see. You shooters keep infiltrating Bird Forum and without being specific about your needs, you get answers from a nature observer's POV.
Let me get specific then. I found the zoom not only had a quite narrow FOV (which may not matter to you), but the image degraded noticeably at 50x and above. Regarding the 50x (fixed) EP, it probably would work pretty good on an 80mm scope but might start breaking down optically on a 60mm scope, I can't be sure but it's my best guess. The 80x is way too much for a 60mm scope. You'll be in the realm of "empty magnification". This is where the image will be larger in size but you'll actually resolve better detail at lower magnification.
I know the military uses Kowa 88mm scopes for their spotters accompanying their competitive shooters. When you need high mag., you'll also need large aperture.
My brother uses a Pentax 65mm scope with an excellent XW10 for a magnification of 39x for spotting shooting targets. He tells me that with decent light he can spot .22 holes at 200 yds. fine, 300 yds. would be a challenge. He also says he wouldn't go any higher in mag. The 50x EP might work for your needs, I just can't say.