Sure,

Based on what you wrote, the goal is to have business accepting btc, correct?

Then remove all the market volatility, and keep it simple to fit their bottom line : sales and cost of tx. Thats it.

There are currently only 2 accredited payment gateway for bitcoin: Bitpay and Coinbase. And their fees are already low. No need to talk much about price of btc etc... just talk about easy to integrate, and fees are near zero. Do tell them that Coinbase has the first $1M in tx for free, 1% after that, while Bitpay has 1% or $30 flat fee.

Think of bitcoin as email. Do mainstream ppl want to understand how emails work? and that they can have their own email servers, ....etc ? I'm sure if you pitch someone into using email you would say, sign up on Gmail, yahoo or hotmail and that they can send mails digitally in sec ....

Anyway, i think i made myself clear enough. English isnt my native language, so i hope someone can contribute in writing for you.