On page 342 of the Marianskis' book they report typical pH values for meat:
pork 5.7-5.9
beef 5.5-5.8
chicken breast 5.6-5.8
chicken thigh 6.1-6.4
that was my thought when adjusting the pH up. There are detailed scholarly articles on meat pH and sausage making, none of which I read before doing this. I like to say, "I was unencumbered by knowledge". I only checked the pH with a test strip, so it's really "sixish". For a tomato sausage with pork I'd shoot for 5.5 best guess. Another sausage type that probably involves pH is so called Buffalo chicken sausage which uses hot sauces based on vinegar.