I and several others have used Gemini Gas Springs out of BC, Canada. Much less expensive than SUSPA, which is the usual FWC struts. FYI, I have a 330W up front on the driver's side, and often carry a 39# canoe on the passenger side. Driver's rear side has 2 traction mats on the roof as well as a 10# cell/wifi antenna.
I have 80# lifters on the front, and 60# on the back. The 60# are strong enough to require pulling down the rear when the canoe is not up there. When it is, the balance is perfect. 80# is not enough with the canoe in the front. Have to work pretty hard to lift that.
Gemini is at 1-778-475-5611 or info@GeminiGasSprings.com I paid $28.07 Canadian each for mine.
Vic