Ya know Sean, you really don't need to buy or build night vision goggles. If you do a test with time and temp controlled and if you find your normal time then you can do a ring around if you insist on this DBI thing. Not saying it is wrong but the guys that use it the most have about 30 years or so of experience. They don't use them (the night vision goggles) Back to the test. Expose a set of negs all the same and then develop them all in the same tray. Lets say our time/temp time for normal development turned out to be 11 minutes so figure out what minus 25% of 11 minutes is (8.25 or so)and pull one neg out at that time and look at it with the green light. Throw that neg in the stop bath. Then at minus 15 % of 11 minutes (9.35) pull another one out and look at it. Into the stop bath. Then at 11 minutes pull another one and look at it. So on until no more negs in the developer. Of course, after 11 minutes we are starting to add time to our 11 so it would be say +15% and then +25%. After the lights can come back on you should see the effects of the minus and plus development. Now if you do that a number of times you will get the hang of DBI and you will start to see what the film looks like under the green light. (It will not look like much of anything for a few times just some off green/white blobs.) And you have not spent time or money on a project that may or may not help you any. That time could be used using the Deardorff and learning about that. This is not rocket science but is something that you have to do past reading and thinking about it. Experience is the very best teacher you can have. It will teach you how to apply what you have read here.
Go for it!