andrewshogun,
Welcome to THR.
Yep, 28" is fine and dandy.
Express Combo guns come with a Rifle Sighted Smooth bore barrel - find one of these barrels and good to go if you find you want a shorter barrel.
28", with a SKeet or IC (improved) and 2 3/4" standard nine pellet 00 buck or my preferred loading - standard 2 3/4" slugs.
Try the Federal brand, of late the Express seems to like these best.
Gun fit, correct basic fundamentals, and become one with the gun.
This the Key.
I personally WANT a bone stock shotgun, with No accessories.
I strongly suggest one learn the gun with NO accessories and IF, and only IF Awerbuck or Cain or whomever the Instructor is suggests for YOUR needs to add something, then do that.
Just a note about "having to have's".
Ireland and some other Countries do NOT allow Citizens to have a barrel any shorter than 24".
Let us hope the US never imposes such a thing here, still, for too many years, the longer barreled shotguns have worked quite well in serious situations.
I was raised to not learn with a crutch, and have options.
Lots of the lessons and all I was raised with, and I/we still do, involve whatever guns the folks have.
Shotguns with long barrels, Revolvers from .22 rim-fire and up, Semi-Auto pistols the same way, an Rifles from single shot .22's, Lever Actions, Bolts- to name it.
Run, what you brung.
Software, Not Hardware.