Are you concerned with getting those last few tomatoes prior to your last frost or overall output?
If what your asking is how do I get those final green tomatoes to start ripening prior to frost then I say try them both. Your goal is to send the plant a clear signal "you're dieing take care of your babies". So all its efforts turn towards getting that next generation ready because I'm not going to make it. So in addition to removing growing tips, and limiting the number of fruits so more effort goes to a limited set of fruit I have heard of "tugging".
You grab the plant and give a strong pull upwards damaging and breaking some of its roots this sends a pretty clear hey you're dieing message. Now I don't know how strong you are but I did pull some 5 foot tall tomato plants clear out of the ground not the desired approach. but just piled the plants on the porch came back 2-3 days later gave them shake and sorted out my ripe ones and then made green tomato relish with the rest.
Pruning the roots by pulling on the plants and thus breaking the root system to a considerable extent stimulates early ripening of the fruit. Of course such treatment early in the season is harmful. In North Dakota two varieties of tomatoes thus pruned early (July 23 and Aug. 17) produced a smaller total crop than those unpruned. Late pruning (Sept. 1), however, resulted in a decided increase in total yield. Plants thus stimulated practically ripened all of their fruits before the end of the season. 17
information taken from http://www.soilandhealth.org/01aglibr...