I've made my share of handrails for my Type VII r/c subs and I started in much the same place that you're in now.
Here are the two methods that I ended up being comfortable with:
For deck railings -
I create a jig to do the construction work with. Essentially, there are two parts. The first is a length of wood that I drill a series of holes into. These holes a spaced to match the required spacing of the vertical posts of the railing. Into these holes, I place the vertical posts, each being cut from brass rod to the necessary length. You should wind up with the tops of the posts lined up all at the desired/correct height. Next, I lay a piece of rod across the tops of the posts and use a little bit of tape to hold the railing up tight to the post.
Once I am satisfied with the way it looks, I remove one of the pieces of tape, typically I start in the middle and work out towards the ends, and solder that joint. You are essentially soldering a 'T' joint so there isn't a lot of brass-on-brass contact to provide strength. To help make it stronger, I use a high strength solder like Stay-Brite silver solder.
If the railing has a mid-high horizontal railing, this is done after the top railing is complete. To do these, I cut individual pieces to fit between the vertical posts. These are held in place with a second set of jigs....whose function is to hold the part at the right height at both ends and yet leave the actual contact area clear so that you can use the soldering iron. Think of this jig as a "U" shaped piece of material that is laying down. The arms of the "U" straddle the vertical post and are used to hold the mid-railing in place. I use a bit of tape to hold the railing part to the "U" jig.
When all of the joints have been soldered, I remove the railing from the jig and carefully hand file the solder joints to remove any excess.
For circular conning towers -
I use a similar approach, but instead of placing all the vertical posts in a wooden jig block, I do the work directly on the conning tower Wintergarten. This makes it much easier to do when the 'verticals' are at any kind of angle.
-hope this makes sense without the use of photos!
p.s. The December issue of the SCR has an article that I wrote about my building the OTW Type VII kit....and I touch upon building the railings there and it has some photos of the railing jigs that I used.