Hey, I'm not sure if Maryn meant me, but I have another set of eyes and a LO closer in age to yours than hers, so here I am
Well, we've gone for kind of set naps from around 10/11mo, actually earlier with the first nap for DD, due to school runs. So both of mine would wake at variable times, but I kind of trained them to hang out in the cot for a bit until our 'official' WU time, so although they'd be awake, it would still be down time. We then fixed the timing of the first nap so that it was the same every day, regardless of the actual WU time - ie when we/CM got back from school. By about 10mo we needed to cap the first nap for DS so that he only did one sleep cycle, ie 45mins, otherwise we couldn't seem to get a decent pm nap out of him whatever we did. DD still had a longer first nap at that age. But the nice thing was that once we were into nap capping in the morning, we could pretty much rely on a consistent am nap, and start to fix the pm nap too. BT would depend on how the pm nap went - and still does, for DD. Does that make sense at all? Not that you have to do it this way, I know that the short am, long pm nap approach doesn't work for all LOs, but we had to do it to work around everything else, and whilst it hasn't worked perfectly, it's helped me to have some sort of structure to the day
So an example sleep routine for DS around 10mo would have been something like:
0630 Up (may have actually woken earlier)
0930 - 1010 Nap (capped - we had to gradually reduce this over time)
1-3 Nap (not always this long, 2h was our ideal and I'd try to resettle if he woke earlier as he seemed to need a nice long one)
7ish BT (depending on how the day went)
If you want to start the day at 7 then just shift the whole thing by half an hour
Of course yours may need different A times etc, this is only to give you an idea. If you post a recent day we can put our heads together and think about what sort of A times might work for you, you may already have an idea...