At the time I was trying to revarnish the saloon table and touch-up other bits of the woodwork in my elderly Sigma362. The standard finish was glossier than "satin" but nowhere near as glossy as "gloss". I used common-or-garden Ronseal Outdoor varnish (oil based) and a rather imprecise mixing method. I tried various proportions of satin and gloss varnish and produced a hardwood test strip which, when dry, was compared with the original, standard finish. I chose what I felt was the best match with the existing woodwork - in my case it was a 50/50 mix, although the difference between the eventual 50/50 mix and a 40/60 and a 60/40 was, for me, hard to detect.
The results were OK rather than brilliant. It looked fine on the saloon table, where I revarnished all surfaces but patching other worn areas was less successful, as any difference between the old and newly mixed finish (very difficult to get a precise match I suspect) really stands out. That said, the results were good enough for me to live with.
Never mixed them wet as it were but have used a couple of coats (or more) of gloss then a final coat of satin (both) epifanes which I have found to give a very satisfactory result.