Yeah in my ruleset, technically the only way to fill empty arms is by "regenerating" with 5 cards from the deck. I had thought about being able to move sequences to empty arms but decided against adding that for the extra challenge.
That said, house rules are always fine by me! (This game was pretty much born from me experimenting with the classic Klondike solitaire, in fact.) Come to think of it, there's a chance I might re-add that and a "magic shells" concept as optional ways of playing.
Anyway, thanks for playing, and I'm glad you enjoyed it!