I switched from the TS to my seat during a break once, and could not easily tell the difference in the recording, if at all. Of course that was a completely different situation.
Normally I tape in clubs, which limits setup to tables, or whatever. I usually make my best guess for location if it is a new venue. Even if I have been there before, I usually find some time to walk around and just listen, to find the best spot, assuming I might have an option to change the next time. A lot of times it is not a problem to slide a table a few feet to get in a better position. I have also thought of marking a big X in the spot at venues that did not have tables, Never thought management would go for that to good, so never did, though.
In short, a couple feet, or one row, can make a big difference at the venue. How that translates to your tape might not be as drastic. That is not to say you should not try to get the best spot you can.