i have the same setup as one of my HD shottys.
i would just keep the 88mav throw a saddle side shell holder on it,place it beside or under the bed & call it a day
save up some cash & go purchase the other shotty...or shop around a little more.i found a like new rem 870 18'' bl rifle sights,tube ex. w/saddle shell holder for $220 out the door a lil while back @ the gun shop down from my work
good luck,stay safe,have fun!