I love throwing inline spinners.  Mostly 1/4 and 3/8 ounce Rooster Tails but I do not like the treble hooks they come with.  Any thoughts on a good replacement treble?  Brand/style/size?

Any of the major brands like owner, gamakatsu, vmc, mustad are excellent options. I’ve tried all of these brands and been satisfied with their performance.
 

Use the same size as the one that is currently on those lures. They are likely to be a size 4, 6, or 8. 

 

One thing you might want to try is going with a single hook. As someone who also likes to use them, single hooks are just as effective, possibly better in the hook up department. The best thing I like about them is they make releasing the fish easier for you and the fish. 
 

 

Some people have a preferred brand.  But not me.  I go with anything other than Eagle Claw, because I've had too many of those rust out on me.  Plus, they're never sharp out of the box.  I've heard their Trokar line are better, but that brand has soured me too much to give them a try. 

 

Besides Owner, Gamakatsu, VMC, and Mustad, I also like Berkley Fusion19 and Bass Pro's and Academy's house brands.  I haven't had a complaint among any of them.

My friends and I swapped out the treble hooks on Panther Martins for inline hooks. The single hooks increased out hook up ration and it’s a lot harder for fish to toss the small treble. 

I make my own and have always used Mustad's and Eagle Claws but I bought them in bulk and haven't had any problems with them.  I've tried single hooks but didn't notice any change in hookups.   Any that I've bought since I get red or black nickle. 

I use owner st-36. super sharp and come in all the small sizes. I think they are a bit stronger than Gamakatsu round bend which I also like 

1/2 ounce Blue Fox replace treble with a straight hook and a twister grub trailer 

The best aftermarket treble on the market IMO is the gamakatsu g-finesse aaron martens trebles.  The standard and the mh hooks are both great options.  

 

They are pricey though.  A really good alternative that is better for price is the Owner ST36 or the Hayabusa TBL930 with the NRB coating.  

 

That size of spinner is probably going to be a #4 or a #6.