you'll be fine on a Brompton a man of your calibre! I have only done one FNRTTC on my Brompton and suffered one of the only punctures I have ever had on a night ride. Unfortunately I didn't have a clue how to remove the rear wheel and had to call for help from some other Bromptoneers. I have since learnt how to fix rear wheel Brompton punctures.I run the tyres it came with which I think are marathon like.