Just have a look at the nutrition label on the tin. That will tell you the total carb content for 100g. and also for the whole tin. Then decide how many to eat, then test your levels to see what effect they had.
I am a cherry tomato fan and never eat tinned ones. Cherry toms with my salads, normal fresh toms for cooking.
Do you have any links to studies on whether they cause inflammation? If they do, I should be riddled with inflammatory problems the amount I eat!. (But I'm not)