First, are the plants you have originally from a place where growing conditions are similar to where you now live? By that I mean temperature, soil conditions, etc. These old-timers were developed in a specific location, so it is somewhat important.

Second, as Sooz says, the only reason to pick off leaves is if the plant is way too bushy - I never do that, and mine do well. In the old days, there were many gardeners that thought it wise to pick off some of the blossoms so the remaining tomatoes would get bigger and better. In those days there was some truth to it, because soil & moisture were pretty much left alone. Now in these days of fertilizer and easy watering that is not the case - I never do that, but I do keep track of the soil type and moisture.

Course, I'm a newcomer to heirloom growing - I've only been doing it about 60 years. And they are bigger, meatier, and (to me) taste better. But they don't ship or store well.

Good luck!