Just use the modified that came with it. You aren't going to use it for special hunting applications, so no need for an extended choke. KISS. Test your patterns on the backside of Christmas wrapping paper at various distances until you find a pattern that suits you.

If you insist on wasting your money on a specialized choke for no reason, review Carlson's catalog. They make hundreds of specialized chokes.

Remember to keep your threads clean and use some good choke grease or you could end up with a fixed choke for life. DO NOT overtighten. Just nice and snug.

Test a bunch of different brand shells to find out which ones eject cleanly. Some AL's and pumps have difficulty ejecting certain shells. If the shell crimp is too long by even a mm, they can hang up in the ejection port.

Have fun.