Yes, I think that it does matter a bit - it tends to depend on which is your dominant hand. The videos that I did are mirrored, I am right handed - I will actually flip them around next time I upload them and replace these.
Coming from a fluent signer/Deaf...I use both right and left hands to sign... it doesn't matter as long as you are comfortable and the person can see your hands signing. If I sit right besides to you, and use my right hand to finger-spell to you, you might have to move a little to understand me, however if I signed with my left hand to you you might understand me better. Really it depends on how the person sees your hands signing as long as you're comfortable.
hope that helps.
@regina.moos thank you very much for that clarification - very useful indeed to have feedback from a fluent signer. This is a (rapidly) evolving project, and all feedback and any suggestions for ways that we can make it better are hugely appreciated!