Methanol injection

[Szutter]

I am removing the DPF/SCR and EGR systems from my 2012 X5d. In doing so I will also be emptying the DEF fluid and draining that system as it is no longer required.
As part of my modifications I am installing a methanol injection system and I was wondering if anyone out there has opted to use the DEF fluid tanks to house the windshield washer fluid or methanol for an injection system.
My plan is to disconnect any systems in the DEF fluid tanks that are no longer required and plumb in a new high pressure pump required for the methanol injection system.
Does anyone have any experience with doing this?
My thought is to try and save space and money by not having to purchase a new vessel to house the methanol.