there is a bunch of reports about sub here
http://www.heroin-detox.com/default.asp
it is an active forum with a lot of conversation and reports about peoples sub use or experience
that being said, ill tell you what I know...I am in no way a medical professional.
1. the reason that bupe is so hard to compare to oxy is because it is a partial agonist, while OC is a full agonist. I have heard that 8mg of bupe is equal to about 60mg of
methadone. To me, about 40-50mg of methadone gave me about the same effect of 80mg OC. Due to this, I would logically assume, for me, that 8mg of sub (which I am on right now) is equiv. to 100mg OC. That is ballparking it so give or take. Bupe is potent stuff that has a ceiling effect of about 16mg. Which means that 16mg would fill any receptors your brain could have. Bup will also increase your tolerance to other opiates (such as OC) so going back to OC to stop your habit may be hard, as after a month, you will probably have to take MORE OC to prevent withdrawals (mental mainly) than you were to get high. If you can deal with it and discipline yourself then go for it, most have problems in this area.
2. Many many people are starting to say that bupe is a beast to recover off of if you are on maintenance. There are a lot of people who said they did a 12-15day detox and it worked miracles, but many people on it over a month claim it to be the worst decision of their life. By what I gather, long term bupe use leads to about the same withdrawals as methadone, and the same length of withdrawals if not longer. Go to the boards listed above and read peoples reports, there is a sufficient amount of data gathered from people to make your decision.
If you are recovering from OC, and are serious about doing it, I would accept the fact that suffering is gonna happen in some form. Its the nature of the beast. There is no easy way. There is a quick way...stay off the sub or methadone. Since your on the sub, it might be wise to taper down to 2mg or less quickly, hang there for a couple of days, cut your losses and go "clean".
Either way, good luck. I am personally trying to quit MMT using sub. I am on a <1 month taper from sub, but methadone changes the rules.