Fentanyl no doubt is a tough one to come off. If you could wean yourself down to the lowest dose possible, then go cold turkey with help from the thomas recipe (and a doc if possible, who can help by Rx'ing some non-addictive remedies and offer support), that would be one possibility.
Some people use Sub the way you've described, but I personally don't recommend it. In order to get the optimal effectiveness from Sub, it's best to do it the right way, with a Sub program that will last anywhere from a few months to a year. There are a lot of benefits to a Sub program, but of course, there are downfalls as well. Eventually, you'd have to come off that too. With a good sub doc and a slow taper, it's doable.
A good sub clinic will incorporate therapy and plans for aftercare on top of Rx'ing the Sub. That really helps you learn how to stay clean. Some kind of aftercare is vital, no matter how you detox. Staying clean is often harder than getting clean. We just had two members with a decent amount of clean time relapse. They're both lucky as they quickly got back on track, but it's a good reminder of how vulnerable addicts are to relapse.
There is no right or wrong way to get clean, everyone chooses a different route. Do lots of homework on Sub, make sure it's for you, and really consider doing an entire program versus using it to minimize w/d's. Unfortunately there is no magic remedy to avoid w/d's all together...and people find themselves trading addictions thinking they can use Subs to avoid w/d's.
Here's some basic info on Suboxone. There's a Part II also.
http://www.medhelp.org/health_pages/Addiction/Suboxone-Subutex-FAQ-Part-One/show/14?cid=66
Very best to you, feel free to ask as many questions as you'd like. You'll get lots of support here, and lots of honest input. Congrats for making that difficult decision to want to make some changes! Way to go!