Thanks for keeping us up on this project. My homemade dual tank system for the deuce is similar.
When switching from diesel to veggie, do you have a fixed purge time or is it instantaneous?
I built a system for a VW Rabbit last year and ended up with two separate sets of fuel lines and filters (heated), so there was no purge time needed. On the deuce and the 8x8, all fuel filters are the same for diesel and veggie, which requires a purge time of about 90 seconds.
Where did you place the veggie tank and what is its capacity?