This is a deep venue, and although I haven't lure fished such rivers before it's very similar in depth to some of the lakes I regularly fish.
Assuming you're bank fishing, my first choice in this situation would be a spoon. My favourite models are the Abu Atom in the 3?inch/35gram size and the larger but similar weight Ryobi Mr. Muskies. Hopefully, Ryobi will shortly be doing a thicker version of this model for fishing down deep or at speed. These may be better suited to your heavyish rod and will probably allow you to cast further.
Both of these patterns will work down to 30 feet, although the speed on the Mr Muskie will have to be kept a little slower than the Atom for a given depth. BTW, the Atom will no longer be imported into the UK after this season.
If you count the spoons down to a different depth each time you'll soon find out at what depth the pike are feeding. You could then switch to a floating plug that dives to this depth. However, if the fish are down deep this will be hard work. Additionally, there are only a limited number of deep diving patterns, so a sinking plug may be better. As each floating plug has a different depth it works down to, you'll need a range of patterns/sizes.
I'm prepared to advise only on topics I know about, so can't help you with jerkbaits as I'm not fit enough to handle such lures. However, I know friends have done well with them in your sort of situation.
As already suggested, spinnerbaits are also a good bet, although most are probably somewhat too light to cast with your rod. If you need to fish deep go for one with a single blade.
I also like soft plasics - have a look at Ryobi's Head Cases, which are available in slow and fast sinking versions. These can be particularly deadly when the pike are in a finicky mood
As the water temperature falls you'll probably need to go deeper and also retrieve more slowly. However, this isn't an infallible rule so it pays to experiment.
As I'm always saying, if at first you don't succeed, try something......different!