Edgun Leshiy 25 Cal. Pellet and Slug recommendations

Hello All,
I am new to the Edgun Leshiy platform. I love it and zeroed at 40 yards. I have been using the HN slugs which work Great. I noticed the JSB Exact King Heavy Diabolo 33.95 grain do not fit in the magazine. I also notice the JSB Knockouts don‘t fit flush but look like they would work. The Zan slugs stick out about 3 mm. Can anyone recommend the exact pellet size I can use in this gun as well as slugs. I do not want to ruin this gun.
Thank you