I have two vehicles, both equipped with a Thule AeroBlade plus a single set of rollers and saddles.
Now that I have more than one boat I find myself moving one set of the rollers and saddle from one car to another when I need to transport two kayaks. I can make it work with two boats on the roof but the fit is not ideal. The one boat (usually a Dagor Stratos) needs to be angled on its side a bit. So I am thinking about getting a pair of J Racks. Does having rollers and saddle on one side and J Racks on the other side work well?
That is a very good solution as long as you can load the boat in the J’s by yourself, or will always have a second person with you. Make sure the feet of the J’s are inside the towers of your roof rack, I have seen J cradles peeled off the outside in a strong crosswind.
I can load a boat solo with saddle and rollers, or glide pads, or stacker.
I have not ever tried with a J-rack and wouldn’t try. I have a tall car.
I suggest stackers for your dilemma. Allows both boats to be on their edge and the easiest to load. Get them up on their hull them flip them to the stacker.
I am generally not a fan of J-cradles, mostly because of the side wind exposure and the fact that I had one fail a couple of years ago. I would only consider a fixed J-cradle, never a folding style. I would only buy well-regarded, name-brand cradles of any type. I still use J-cradles on my trailer but the top is attached to the trailer framework in addition to the bottom attachment point.
Neither am I. I had a Malone J crack while it was on a trailer. Fortunately, I found the crack before it came apart while in use. Someone told me hers had cracked in the same area while on a car roof. Previously, I had used some Thule J cradles, which did not fit my kayak well.
Kayaks on their sides catch more wind, put simply, even with a cockpit cover on. I suspect this puts too much torque from the kayak end to the J cradle. Metal J cradles probably fare better.
I noticed a drop in mpg going from upright on foam blocks to sideways in J cradles. And that was on a trailer. I quit using J cradles after the crack happened.
Wind should not be an issue. This will (mostly) always happen while out on Orcas Island where the road speed is under 40mph.
There is one of those focused rack businesses in Seattle. I will try there even bough they burn through low inventory at a furious rate. More impact from Covid I guess…
Another option, is to get longer crossbars. Then you can fit two roller/saddles.
Unless you are tall or the car is short J-bars can be difficult to solo load compared to saddles, especially from the rear. Plus there is the crosswind issue.