The Reactor cover on the Tropicals is a new, strong cover. It's used on everything from the Tropicals through the Fire line up to the original Agent and some Banshees. Without a really weak drilling, I don't think it's your best choice for spares/dry. If you want something that's weak enough to use for spares, consider the Slate Blue Gargoyle. It will be pretty straight on any normal amount of oil and will work on drier lanes.
You might be able to use a Hit or Barbed Wire if you can find one, if you're trying to stay with Storm. Even then, I'd get a plastic ball for spares; you'll probably use it much more for spares than for dry lanes, getting a reactive ball just in case you see dry lanes could mean missing a lot of spares.
SH