How do I sell a Saas product online that is usually sold over the phone?

We are about to test the willingness of visitors to our website to 'buy now', as opposed to the usual method of 'get a demo' which would hand them over to a sales team who would call and close over the phone.

We are only testing this approach on users that would require a very small # of users. Traditionally, when this demographic reaches the sales team after requesting a demo, they don't even end up seeing a demo at all, the sales team just sell it to them verbally. Everyone else gets walked through a product demo / sales pitch.

The software is b2b, it's not ubiquitous, and it's relative suitability to a prospect is not always crystal clear, hence sales teams being required to close the deal. There are too many questions involved.

The Saas software comes with a long-term contract (at least a year), we can't offer a free trial as we also send out hardware to the user and we can't offer a login to a dummy account to have a play around.

What would be some good approaches to maximize our efforts?

I've arranged to listen in on some sales calls to extract any objections and counter objections, but I'm looking for some advice from someone who has done this before on how to sell a high commitment product with no touch involved.