Re: Ubitx only on preorder now
I did this for a scratch built SA612 receiver recently, have a look at the vid here: https://vk3hn.wordpress.com/2017/08/28/an-ssb-receiver-from-an-arduinosi5351-vfobfo/
The sketch allows you to shift the BFO just like it's the VFO to get best placement in the filter passband. This is by no means original, several others' sketches allow this.
73 Paul VK3HN.