Damage to insulated trunkline questions

Hey all, been a while.

I have a question about my particular situation.

The set up is this...
Four years ago I had a TVA audit to replace my compressor/airhandler/trunk/ducts. I ended up with a 4 ton two speed compressor connected to a variable speed air handler along with 40 feet of main trunk which is square, tapers and is insulated on the inside feeding 14 separate ducts. This is a two piece system with the air handler in my crawl space. The trunk has dampers which were balanced for air flow. The whole system was sealed with mastic and mastic tape. TVA came back later and said "good to go"

Couple weeks ago I had a service water leak in the kitchen. This flooded the kitchen, dining room, and part of the living room. Water went into three of the ducts and made its way to the trunk line. The insulation in the trunk acted like a wick and the water traveled the 40 feet to the air handler. Luckily there is a condensate pump at the air handler which removes excess water.

Original contractor wants to replace the 40 foot trunk along with 5 flex duct runs. Rebalance with dampers and have it exactly as it was. (square trunk with insulation inside).
Insurance company DID NOT LIKE THE QUOTE. Specifically they felt $57 per foot of trunk is excessive. Contractor countered this is a CUSTOM system and the cost to fabricate the square trunk on site is expensive. Insurance asked me to source another contractor for a second opinion. which I did.

New contractor agrees to do everything plus sanitize remaining 9 flex ducts for about 20% less. The difference is this. They want to use a ROUND TRUNK insulated on the OUTSIDE.

So I guess the round trunk insulated on the outside is less expensive than fabricating square trunk with interior insulation on site? What is the difference and what are the pitfalls? Is one better than the other? They stated the round was galvanized steel just like the square. The insulation on the round is R-8. I remember the insulation on the square it was about 1 inch thick black mat material unknown R value.

Thanks for reading this and responding.
Matt

Seems like the difference is that the first contractor wants to bring in the material and fab the ducts onsite. The second contractor is going to used ready-made ducts (i.e.- less labor).
The only difference between round and rectangular ducts would be the ease of tapping into them (as far as I know, I'm sure there are more differences to be considered).
Have the second contractor put in writing his CFM's for the system and hold him to that.
Optionally, turn on the "Heat & Fan" and dry it out for a few days.

Its been 2 and a half weeks. Still wet in there. All around seem to be worried about mold and mildew. I cut two of the flex duct runs to drain the water. The insulation is still soaked.

Not to mention its mid August.

Sounds like insulation on the out side would be a better idea, the reason for square is to make it fit beter and take up less room.
But still you insure a Caddie and the want to replace it with a chevy??

Not me, the insurance company is questioning it.

I know nothing about it, is one better than the other? Is one really a caddy and the other really a chevie?

Then the question is why did the first guy sell you the more expensive duct if the round pipe would have worked.