I've got from the Renaissance era to the Internet before I ran out of steam by bulbing only one GS. I was waiting until I reached the Industrial era but Monty DOWed me leaving me with one city. I finished having to complete combustion in 177 turns...... You don't need to start the exploit but use the mechanic legitimately. You can purposefully research techs to 1 turn then research another, creating your own overflow(although not very large). Any overflow got from RA's or GS bulbs can be spent in techs that wouldn't result in a 1 turn completion, thus breaking the exploit.