What is the best 'big' mirror option for mid-bar clamp?

I have an R6 with streetfighter kit, so I have a 7/8" diameter drag bar. My dad and I had some fun in the garage one day cannibalizing an old bike handle with this huge and convex mirror on the left clip-on slot--it feels very safe. I'd do the same for the right side but I don't know where the mirror part even came from.

On the right side, I have tried a few vintage eBay mirrors to clamp from the middle like pictured, but they tend to sag or didn't reach or provide a comfortably large angle of rearview. Also note that I need a mirror rod to be long enough to clamp in the middle (where i have space on my bar) to about 8 inches away minimum to get a good view behind I don't want bar ends cause I have narrow clearance where I park. I bought this quality DRC clamp that claims to be universal. (I tried an acerbis mirror and I felt scammed.)

Can anyone point me to a good convex mirror with a 8" reach and something like 3" diameter? Or let me know a good way to craft this from what I have? IDC about aesthetic I'll make it work. Ideally under $150 new but also flexible on budget.