Nice bike. If you want to use them, do. You should be well and truly fine. Fabian Cancellara uses Ti spindled speedplay pedals and he is both over the weight limit and a hugely powerful rider. If you have broken cranks in the past, maybe use the SS ones. Even so, they should be fine. If they are not, you have a warranty and a spare set of pedals.
FWIW, speedplay cleats (soft brass and fast wearing) + Single speeding (hike-a-bike) is probably not the best combo, but yeah, other than that, you'll be fine.
FWIW, speedplay cleats (soft brass and fast wearing) + Single speeding (hike-a-bike) is probably not the best combo, but yeah, other than that, you'll be fine.