DXM before methadone dose - experiences?

[Benzo-'Done Cuffs]

Hey y'all, so I'm a Greenlighter and have been doing some searching on people taking DXM before their MMT dose which temporarily lowers their tolerance, thus making the dose feel stronger/last longer (?) My end goal is just to make my methadose last all 24 hours, I already take tagamet 400mg (2 tabs) 40-60 mins before dosing...
So as my username suggests I take methadone and prescribed Klonopin (plus Xanax) daily and am now on 120mg. I never thought I'd eeever let myself get to this doss let alone use on 'done maintenance. But I truly have a very fast metabolism; I am 5'4" and like 130, while many people including my gf have had weight gain issues on Methadone...
I guess I'm looking for any experiences with people on Methadone that take DXM to potentiate/make their dose last. If it lowers tolerance, than would taking it everyday be bad? I wake with some cold sweats, achey and very cold at 18-20 hours some days. Or maybe I should stick out the bad days and use DXM when I start tapering (hopefully soon after once/week or less slip ups on H). I haven't used in about a month and increased about 3 weeks ago but still... Any input or experiences appreciated