That is great news that your deals are working well. 100% uplift is a great achievement for you, especially with a good margin too. You would typically factor in 50-100% uplift. This is great data for you.
We always recommend you make sure you have enough stock for a deal, especially as you have to pay Amazon for the deal set up. (although deals are much much cheaper to run in Europe vs USA). That said, running a 7-deal for one day doesn’t always cover your ‘deal costs’ paid to Amazon, so you need to factor that in because you may not have broken even on the overall sales yet.
It sounds like your product could benefit from a basic price drop if you needed to boost sales. This would save you the setup costs.
But back to your Q. — Yes you want to avoid being OOS at all costs. So plan your inventory accordingly. Depending on the day of the week, Monday and Tuesday are normally higher sales days anyway, so you may see a drop off through the working week.
You may need to cancel your deal if there is any risk of you going OOS.