I recently discovered Gimme Leftist to be a very forgiving blend for a cappuccino. The shots pour beautifully and they really stand up well in milk. We also love it as an americano. It is mild in the sense that acidity is low, and chocolate-caramel sweetness is high. However, it has some punch to it, so it might be too strong for your palate as a straight shot. If you are looking for something similar to the original crowd-pleasing Black Cat, I would try out the Leftist.
There are milder blends out there more suitable for straight shots. You might look for a Brazil Daterra Estate coffee. It is a clean, high-quality blend of smooth Brazil crop produced by one of the most technically-advanced farms in Brazil. You can
read more about Daterra on Sweet Maria's. Brazil Daterra is the magic behind the ultra-mild Illy blend. Of course Illy itself is stale and overpriced, so I do not recommend it.
There are many roasters who offer Brazil Daterra... one notable one is Terroir. However, I wouldn't start there... many people find it necessary to push certain parameters out of the "norm" to achieve optimal results.
Ecco Caffe is another roaster with excellent Brazil offerings... however shipping to Florida will be slow and they are pricey.
My favorite Brazil Daterra (in terms of price, shipping speed, AND taste) is from Tony at Caffe Fresco. He has not been taking online orders over the last few months much to many forum members' dismay. However, your timing is perfect because he will resume selling online this Friday. I would definitely encourage you to check out
http://www.caffefresco.us/ in the next few days.
To summarize, Caffe Fresco's Brazil Daterra for straight shots... Gimme Leftist for milk drinks. Both are reasonably priced and forgiving. I find the Daterra milder at slightly lower than average temperatures, whereas the Leftist pulls sweetest around the typical 200F.
Regarding the 408 from Barefoot... I wouldn't recommend it as a "forgiving" espresso. Barefoot roasts very light and in my experience requires pretty specific temperatures and doses to extract the maximum sweetness from their coffees. That said, they are a top-tier roaster to keep on your radar.
Please do report back on what blends you choose and how they turn out for you!