My Mk4 Defender Loadout. Thoughts?

So here's my Mk 4 Defender. I'm contemplating upgrading my epic sniper cannon. I ran tier ii uncommon sniper alongside my tier iii cannon for a while, but couldn't get another uncommon sniper to save my life. Now I finally got one after spending thousands of uncommon parts on my exploding cannon. I do like the blast cannon, though. My infamy has gone up since switching to the exploding cannon. I'm at the level where I can start training sniper to have a decent crit hit chance, and I have epic parts to spend. Could probably get the sniper up close to level 10.

Red Items
I'm tempted to upgrade the Big Bertha to tier iii, and I also have 3 Rare Long Range mortars I could combine. Are they worth investing in? As you can see, there's some other options as well, with the big torpedo, the napalm, and the flare gun. What I really want at this point is a good firebomb, but the game hasn't given me one yet.

Blue Items
I feel pretty good about my blues, especially that turbo. Defender is dead in the water without one. I have 5 rare bandages in total, and could potentially run two good ones instead of one great one. Is it worth it to drop the rare standard shield and rock two bandages, or should I just keep upgrading the one I have until it maxes out?

Thanks for any feedback!

 

your setup is ok for me for the mean time maxed out what items u have until the moment the game gave u duplicate items and enough sugar for the training

 

Find 2 rare sniper crit perks (+5% chance to crit) then you could rock the sniper. I've seen defenders doing best with a sniper and a cannon