Toilet training during naps:
Our first attempt at this resulted in him staying dry during the nap, but when he woke he sat up and wet his pants before calling out for us. We have a great waterproof bamboo mattress protector under his sheets, so it was just a matter of throwing it all in to the washing machine (and the protector into the dryer once washed, as we only have one). Not a big hassle.
The next day he stayed dry, although i think he woke from his nap with a nightmare as he only slept for an hour and woke crying and calling for me. I raced him to the toilet but he actually didn't need to go. Daycare are putting him in a nappy for his naps, but they say he mostly wakes dry.
I'm finding it easier to put him in a nappy for naps at home though, as he's often reluctant to go to sleep, and it's while he's calling out for me and pottering around his room playing that we get the accidents.
Update on toilet training:
It's been 4 weeks now since we first started. He did super well at first, with only one or two accidents a week, but seems to have regressed slightly. He holds for around 2 hours before he'll agree he needs to go (i usually ask about every half hour), but we're on about 2-3 accidents a day. His better days are when he naps for two hours. Usually it's only wet undies, as though he's started then realised, and is able to stop, but there was one day last week he wet through 5 pairs of undies and 3 sets of trackie pants. He won't always tell me if they're wet, but at home he'll call out, "Wee," and i ask if he needs the loo, and he'll say yes, and that's usually when i've found they're slightly wet. I think that's his way of telling me. He used to say, "Uh oh, wet!" which was a lot clearer. He can actually get on the toilet at home now as we bought him a ladder with attached seat, but seems to insist on Mummy pulling his pants down, "Mummy turn!" which i think is increasing the likelihood of an accident by his need to wait for me (this evening i was upstairs changing sheets when he called out, and although i went downstairs straight away i think it was too late).
Naps are in a nappy and i find mostly it's dry. He's also getting a drier nappy at night, although some nights they're soaking. Not nearly ready for night training yet. I think not until he's fully day trained and nappies are consistently dry at night. Don't fancy changing sheets in the middle of the night, especially with lack of sleep from a newborn.