ammo issues gone, flipped the sniper to .50 call and made up 500 ammo from lead weights
That'll do it for a sniper. There are a few gyms in FO76. IIRC, the easiest ones to get lead weights from are in the club just outside Flatwood on the road from the Wayward (the weights room is next to the pool) and the Charleston fire department. For a pure sniper, you might be able to pick up enough lead just from scavving stuff as you play. Pre-war USA in the Fallout universe had a usage of lead based on the worst of real world lead usage in the modern era. Which is true for pretty much everything about pre-war Fallout USA. So in FO76 you can scav quite a lot of lead from picking up paint, children's toys and various other things. Paint is particularly good for ammo-making because it gets you lead and steel.
is collecting PA bits worth it before high levels?
Maybe, only in the context of collecting a full set by the time you've levelled enough to use it. The only PA you can reliably learn to make yourself before getting close to the endgame is Excavator PA. There's a side quest for that triggered by visiting a certain location and looking at a certain thing. You'll probably do so while exploring, but if you want details you can easily find them online.
If you do decide to try to collect a set, there's a specific way of doing it that will save you a huge amount of carry weight and/or stash space. It's not an exploit - this is how PA is supposed to work in FO76. The key point is that PA pieces are heavy when not on a PA frame but weigh nothing when on a frame even if it's a frame you're not wearing. That might not make any sense in a realistic way, but it's how it's supposed to be in FO76. So the method is this:
Find a PA frame that has spawned in the gameworld. There are many PA spawn points. You've probably found some already.
Look at it and select the transfer option to move armour pieces from the frame into your inventory if those pieces have a level requirement above whatever level you are at the time
Exit the transfer screen and enter the PA frame (you can enter a bare PA frame at any level - the frames themselves have no level requirement). That makes the frame yours. You can put it in your inventory, put it in your stash, whatever. If you exit it and leave it somewhere, it will auto-return to your inventory in (IIRC 90s). To get rid of it, you'll have to get out of it and drop it or sell it.
Exit the PA frame.
Look at it and select the transfer option and put the pieces back on what is now your frame.
Exit the transfer screen and collect your frame with the pieces on it. The frame weighs 10
regardless of what pieces are on it.
I did that and had a full suit of L25 T-45 PA armour ready to use when I was L25. Which I might have used for maybe as much as a day while I gathered material to make my first Excavator PA suit, which also has a level requirement of 25. Or I might not have used it at all. I'm not sure. I also spent a while collecting pieces to make full sets of max level T-51 and T-60 suits, neither of which I ever used. So maybe not really worth it
I just leave them on the frames now, in case they're useful to another player who comes by.
I would suggest collecting some fusion cores, though. It would be annoying to have your first suit of PA ready to go and then find you only have 1 mostly discharged fusion core for it.
Since L25, I have only used Excavator PA. I made new sets at L35 and L45, but I've always used Excavator. It has low protection for PA but it has +100 carry weight and with the way I play that's a bigger advantage. Horses for courses. With the mods I've crafted for my PA parts (calibrated shocks for the legs and a +2 strength mod for another part, I forget which), I have a carry weight of 420. I'd find it bothersome to have it reduced to 320, which it would be with any other PA suit.
Is the Strangler power armour better than the T65? I got the impression that only the T65 is worth having.
Depends what you mean by "worth having". Purely in terms of how much protection it gives, T65 is the best. But I rather fancy pootling about in a weird-looking PA, spraying acid at my enemies like some freaky alien thing. Just for jollies.
What I am gathering bullion for is the jump jet for the Secret service armour (which isn't power armour). I rather fancy that.
Do you know how it's powered? Although maybe it wouldn't matter so much. I don't use jetpacks with my PA because they drain fusion cores too much for my liking, but if I wasn't using PA fusion core draining wouldn't be issue. There is a certain something about a jetpack, although if I did go with unpowered armour I'd probably just use BoS combat armour because that gives the most protection for unpowered armour. I'd feel soft and squishy outside of PA
The other thing I'm trying to find is an anti-armour handmade rifle. Anyone seen one?
Maybe. I have several legendary handmade guns in my stash. Maybe one is anti-armour. But they're not for sale. I might go back to a rifle build some day, so I'm keeping all of mine.