One of the reasons we use RDBL as part of our escape mechanism when 1NT is penalty DBLd is having been bitten once by redoubling on a strong but unbalanced hand. After that, we came up with a system for handling hands like that after 1NT-DBL. Chip & Lew still play it, but I have given it up as too much of a memory strain

. It involves transfers from 2NT through 3
♦, with the transfer bids showing either a weak hand with the next suit or a good hand without it. So, for instance, 1NT-DBL-2NT is either a weak hand with clubs or a strong hand with diamonds + a Major (shown by 3
♦ after opener's 3
♣), or a strong hand with both Majors (after 3
♣ by opener, 3
♥ is less strong than 3
♠), or a strong 4441 or (544)0 (shown by 3NT after opener's 3
♣). The other two transfers are similar.
As for the actual hand, I asked Chip what he thought, and he said he would bid 2
♦ over the DBL, showing diamonds and a higher suit. He said that he did that not because he was convinced that 1NT would go down, but that because if he didn't bid now and the opponents ran, he would have no way of showing a 2-suited hand, and if he did compete, partner would expect more values (our Pass of 1NT-DBLD is to play, sometimes because we think we'll make it, sometimes because we have no place to go).
Jan Martel, who should probably state that she is not speaking on behalf of the USBF, the ACBL, the WBF Systems Committee, or any member of any Systems Committee or Laws Commission.