Seeing holes at 100 is one thing and 500 is in another league. And holes in the white are one thing and in the black is another at any distance.
First id reccomend using all white targets with colored aiming dots being small as possible.
At 100 yds and even further, a sharpie x on the white paper shouldnt pose any problem for the 20x leupold.
Since your familiar with Kowa there would be good choices used on ebay within your budget.
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