Hi @Gordie… it is not a matter “if it works”!..
Sparkle is a very capable free-flow design platform for creating outstanding websites, minus all the hassles of the common issues with “responsive fluid” web design - Sparkle is “responsive fixed”. In the end it will be you behind it (Sparkle) that will make it work or not.
A reasonable sound knowledge in web design and development for paying clients I feel is a must. I mean they will becoming to you for professional advice. Also having a good understanding how far you can push Sparkle would be a great help. That knowledge allows me to know if I will take on the project or not.
I’m here in Australia so I rent space on a Linux-based sever running the latest PHP, that allows me to service our own clients. Sparkle uses a little bit of PHP for the form and the Blog Index page, so PHP is important. I have never had an issue with our clients over nearly 3 years hosting a Sparkle website!
Mmmm… The workflow in the end is a personal thing but like Primo pointed out, it follows a pattern. What I do is get the most I can out of the client through a questionnaire > then interview > proposal / contract > plan on paper or iPad > prototype (sometimes I do this in Sparkle, or sometimes in Sketch and import it into Sparkle) > information architecture (including 3rd parties if needed) > design (client has access to a development platform to view milestone progress) > SEO > test > launch to the world wide web.
In some cases a pitfall could be clients not being able to make simple edits to their Sparkle generated websites, but there again I only deal with clients that just want to get on with their business and leave everything website up to me.
In the end your side hustle, possibly become business, is your creation. And the way you run it is totally up to you and in the end (if you don’t flip-flop) you will attract the clients that prefer your way of building Sparkle websites and maintaining them.
An extra tip - If you are good then charge a good price! Don’t base your services on price because you will get the clients “knocking on your door” based on price and looking for the cheapest… and those sort of projects never end well, mainly for the Designer!
I hope that is of help, and good luck!