I love the design and everything. Reminds me of my Portaspresso Rossa; I absolutely love the coffee from that. I have two issues though that would prevent me from purchasing: temperature and pressure profiling.
With everything you have built, you should be able to pressure profile. Long slow preinfusion and a decreasing pressure while pulling to maintain a constant flow rate. I drink light roasts and this is pretty much required to do to get a nice syrupy, flavorful espresso. You should showcase this feature. For me, this is one of single most important things about lever machines. Prove that you can pull off these with very fine ground espresso and people will be more interested.
The profiles I usually use for light roasts:
10-20 seconds of water just touching the puck
10-15 of preinfusion of 2-3 bar until beading
40-50 second pull with a profile of 8-9 bar until proper flow with constant decreasing pressure down to 4-5 bar for the length of the pull.
I aim for 16-18g coffee in and 2.25 times water volume out.
The second aspect being temperature is a universal element. Different roast levels and origins require different brew temperature. You need to be able to prove that you can get the temperature above the puck between that 195F and 205F. Those are the minimum requirements since those are the agreed upon standard for coffee. That's what it takes to dissolve those coffee solids and get the proper extraction. Check the temperature of the coffee output compared to a standard machine you own as well.
I would also invest in a TDS meter of your choosing and post those results. Most individuals look for the 20-21% extraction. Some prefer higher or lower than those numbers, but you want to achieve around this. SCAA has the optimum range from 18-22% for reference. SCAA numbers are for your benefit. Plus it provides a standardization that you can wear as a Medal of Honor.
Once you can prove your machine can accomplish these feats, you will sell more machines. Your machine is designed for coffee enthusiasts and these are some of the standards we look for. Hope this helps.