How to estimate Scoville level of home-made pepper sauce??
This can be a party activity for your friends.  The Scoville test is a dilution test, so you can reproduce it at home at least as far as informing your friends is concerned.

Get a lot of distilled water and a bunch of milk and plain bread.
Create dilutions of the hot sauce by adding 1ml of hot sauce to each of 250ml, 500ml, 1000ml, 2l, 5l, and 10l of distilled water.
Have each of three friends blind taste test the diluted sauce against a glass of plain distilled water, starting with the most diluted.
Cleanse palates between rounds with bread &amp; milk.

The dilution at which the hot sauce's heat cannot be tasted by any of your friends reliably is its approximate Scoville rating.  Yes, it's not quite how the actual Scoville test works in the lab, but even if you don't get a rating out of it, it'll be a fun thing for your pepper-loving friends to do on a Sunday afternoon.