we used pu/pd with our ds around 8months, and it worked a treat, took a while to take effect, and we also realised that being such a busy boy he needed a good 20mins windown before any sleep. Dh and i decided we'd not do pu/pd for day times because we didn't have the strength, and found that the winding down before the nap sorted the daytime nap out well.
We also felt is was weird to be in the room with ds, but paradoxical approaches often work.
our method was to go into him when he cried, soote with our voice by side of his cot, if he still cried then scoop him up in our arms, like a fork lift truck manoever, and the moment he stopped put him back down, all the time telling him what we were doing ('i'm going to pick you up now i know you're upset, when you're calm i'll put you back into your lovely warm cot') and kept doing that relentlessly.
When he stood, we did't pick him up we just laid him back down repeatedly saying the same stuff,'i'm going to lay you down again' if he was hysterical we'd pick him up and when he was calm put him straight back down.
once he was calm and going to sleep we'd keep our hand on him for 5-10mins and stay in the room with him for a good 20mins to make sure he'd gone to sleep. One thing that pu/pd does i think is knacker them, but that means the falli nto sleep harder and jerk as they're about to fall into their deep sleep, and this can wake them, if they can feel your hand or see you they don't wake up again and the go to sleep restfully.
Over time when you're only having to go in and put him back down you can take your hand away and use your presence and cut back the time you're in the room till eventually either you just go in put him back down say night and leave, or your voice from the door does it all.
we got to that point then he got very ill a 11months, and since then we've been all over the place as parents and at 18.5months we're in sleep hell again.
This time round i'm so blimmin tired and fed up i'm thinking of going to millpond to get their advice, i've heard they're great at solving sleep problems.
good luck. i wish we'd stuck to our guns because we had him sleeping through and even if he woke it was a 5min up there, put down, hover by the door and out. Now we're sleeping on his floor, it's grim.