Just to chime in: OP, have you ever used subs before? I can't imagine you'd need more than 0.5-1mg daily to stave off withdrawals considering your habit. 0.5g over the course of 3 weeks? I'm not sure if I would even risk using suboxone. My habit spans 7 years, and I have resorted to sub maintenance, but truthfully, it is a nasty drug, and it's not going to leave you feeling great.
I understand that you want to be functional, and you seem to label your withdrawal syndrome as 'severe' because it is devastating to your functionality, but the symptoms you are experiencing are comparatively mild. I'm not going to sit here and try to convince you that 'you got it easy', because heroin detox sucks no matter how you slice it. And honestly, I had more success fully detoxing from a 1-2g a day habit than I did when I was chipping, just because of how debilitating the WD gets when you have a heavy habit. The biggest temptation, for me anyway, comes when you're partially mobile, rocking back and forth on the edge of the bed counting the minutes, and surprisingly not during the super-acute, 'accidentally shitting yourself in bed and then laying in it for way too long because the thought of gathering your clothes, trecking to the bathroom and hosing off is too overwhelming' phase.
I honestly think you'd be best served by clearing 4-5 days from your schedule, climbing under the covers, taking enough xanax and clonidine to relax and sweating it out. Loperamide might be the ticket for some of you lingering symptoms, and it's easy to taper... but if that's not cutting it, I'd bet you could use kratom during this time to almost completely wipe out the rest of your symptoms.
If you cannot take a few 'sick-days', I think you could cut your 8mg suboxone into 16 pieces and take 1-2 pieces daily to remain completely functional, but after you run out, you're not going to feel fantastic. You'll have to budget for a few shitty days regardless of which route you take. If you go CT, you could be back to prancin' after a long weekend