I just want you to get the B12 into your blood stream as much as possible.

I used to chew up the Jarrow and swallow. I switched to Puritan's, which is very soft and soluble, and I swallow them too.
I even ground up Puritan's and gave to my cat who was very ill last fall (finally diagnosed with mast cell carcinoma). She really showed positive response, when the vet thought she had inflamed intestines. I put it in a little whipped cream.. 3 times a week!
She no longer seems to need it, she went into a remission with steroids and is still with us, months past her estimated life span!

It is not a big deal to take on an empty stomach. It is certainly easy, and not uncomfortable like trying to hold in the mouth for long long minutes! Rapid dissolving does not imply rapid or complete ABSORPTION. Lipophilic molecules, meaning FAT SOLUBLE are the best candidates for sublingual absorption. B12 needs intrinsic factor to get thru the membranes of the GI tract because it is present in food in 2-5mcg amounts. Not because it is quickly dissolved.

Do what you want, however. In this case it will show over time if it is working for you, when you get retested. Just keep in mind you are swallowing most of it anyway, therefore empty stomach at the time is best.