Great info. I honestly can't imagine going over 300 grains with this rod. For me, it's a a true super light single hand/switch and I'll use mostly dry flies with a Scandi head. I have a TNT 1195 that's very light but can throw just about anything with ease (extra 9 inches over the Helios)
I also have a TFO DC #4 11 which can barely toss a 3inc leach with barbells. I wouldn't do it again, it loves a 240-275. For me, I prefer lighter lines for both the fish and I find them less work on the water.
When you get north of 325 I feel as though you're entering robust 5 to light 6 weight which isn't really what I need. It's a lovely Rod and truly lightweight and I'm hoping it will give more feedback than the TFO. (Not that the TFO is bad in any manner, I love it)
I use to use poly leaders, but I don't find them useful unless I'm throwing skagit and need to get down deep. But I use a lot of weighted flies and I rarely need both a sink tip and a cone head. I'm sure you're environment calls for that (and I'm jealous) but here, there's just really no need.
I think people overweight their rods more often than not (not suggesting you do) but I find I get more out of my Rod the lighter I go in grains.
I try to stay around 300 or less. I'm impressed if you manage 370! I'd drive her slow though
