Say L
I did the same thing this year with my 11-87.

Added a Rem choke 20" Cantelevered SP Barrel
Added a Nikon Monarch 1.5 x 4.5 scope

kept my Hastings .663 extended choke

Dialed this in at 10 yards with trap loads until I punched out a quarter sized dot dead on.

Moved to 20, 30, 40 & 50 to determine pattern with Winchester Supreme #4

Tried #5 and #4 Hevi Shot and gave them away. Will never buy another.

Paterns very nicely with the Winchester load.

JW