How much backing does one need when fly fishing for Pike?

My baitrunner reels carry 300yds of 50lb braid, yet I don't think I've ever had more than 150yds out at any one time, even after a run. My bait casters have much less, but when lure fishing I've never been close to emptying a spool.

I'm looking for a reel to go with a Greys Platinum XD Saltwater #9 and have settled on the Greys G-Tec which seems to have a good drag and is selling for £99 at GAC.

However, I can't decide what size to go for; the 380 = WF7 + 110 and the 410 = WF9 + 258. I can't help thinking that I need something in between the 2, as with a #9 line I don't imagine I'll need +250yds of backing. Plus, the larger reel will no doubt add weight and bulk to the setup.

How much backing do I need with a #9 rod? Will the 380 be sufficient, or should I go for the 410, or look for something in between?

Thanks in advance.

Go for the #9, not for backing capacity either, but for the line weight to make life so much easier when fly fishing for pike. Trying to cast an 8" fly with a #7 will have you banging your hrad a gainst a brick wall.

#9 really is the least you SHOULD be targetting pike with too. Yes, you can catch pike on a #5-7, but you shouldn't. It isn't good for the fish and pike are under such tremendous pressure from all quarters now that we need to treat EVERY one with care. A 3lber will still have your #9 in a hoop.

As for backing capacity - you will be lucky to get a pike run any more than 25 yards, even big ones. They are more of a dogged fighter than a searing run figter. Fast short runs, not long singing ones. Line capacity is not an issue for pike, but it is for filling the reel so it is at its most efficient.