I've had more success with httj (even though he is not exactly jolting). DH is also 5mo and I've been doing this for at least 2 months
, but generally have pretty good success, as compared to at the beginning. Usually i go in at the 35 minute mark. However, if he has trouble going down or is OT, he might wake suddenly at 30 minutes so I now generally go in then just in case. What I do is hold down his arms, basically to prevent him from stirring. W2S would not work for me as 30-35 minutes is right when he comes up from deep to light sleep. If he's not OT he generally passes through this shift okay with me holding him. Occasionally I have to put in the soother. If he wakes fully I end up picking him up and patting, rocking, anything to extend the nap (my experience is he is better if I do that than if I accept the short nap - it just really messes with the day). DH will also stir at the 45 minute mark and then sometimes at about an hour. Usually between 45 and 1 hr he transitions to deeper sleep. Lately he has sometimes woken at the 50 minute mark after not stirring earlier (could be undertired).
I know, sounds very detailed but I've learned a lot about his sleep by sitting those hours by his crib. I is definitely time consuming but for now I am willing to do it. Apparently they are supposed to mature out of the short naps. I suspect it will only happen for us once dh is going down independently.
Also I notice your second A time is pretty long. DS still only tolerates about 2hr or a little more of A time. Less if short napping. That could explain your difficult settling at catnap and bedtime - your lo is likely OT by then.