Peppers should be blitzed whole?

On whether to use the peppers whole or trimmed - recipe doesn’t say, so your choice.
If you leave them whole, you’ll get more heat.
If you remove seeds and membranes, you’ll get less.
On choice of peppers - these are some of the hottest.
If you want or need to replace them (what’s available in your markets) look up the Scofield chart, which scores peppers by mildness and heat.
Then buy ones in the same level as recipe recommended.