Left2Lobster2020

Hi, I’m new here and I had my first 3 gun match and placed middle of the pack out 35 people who were there. I’m pretty happy with how I placed. Most importantly, I had fun and I was safe. I used a CZ 75 Tactical I had which I did very well with. I did very well with the AR portion with my home assembled rifle. I struggled with my shotgun. I brought my Mossberg 930 tactical in 12 ga. I have the irons dialed in for slugs and a red dot dialed in for 7 1/2. I left my Versamax 12 ga (28” barrel I believe ) at home as I have it set up for turkey hunting a couple of time a year. I know this is the better option between the two shotguns I have. I’m in the homework stage of what I want to do next. I’d like have a longer magazine tubes (thinking +9) when I compete again. If I do this to the Versamax can I remove the tube extension and return it back to original configuration? The other option seems to be to put a 28” barrel on the 930 if I can find one and mag tube extension. The concern I have here is the rear ghost ring on the rear receiver with the front bead and this becoming more cost prohibitive (21 bids on EBay at $330 for a 28” barrel with 2 days left and with none in stock anywhere on google) I’ve had experience with Nordic in the past. Any other brand recommendations for brands? Thoughts on the options? Any choke recommendations on the Versamax for 7 1/2 shot? Thanks!