I know of one guy who put spacers under the Front Mounting, to get a more raked position. Doesn't help, I know.
ONE thing, at now 6-1 (lost over an inch in last ten years) I fit MUCH better in the X150 than I did in my old XK8. Again, no help from me. Sorry.

Something I have to do when I got new seats for my Corvette is leave some weight in the driver's seat if not being driven for more than a few days. About twenty pounds works.

Losing weight will work as well.

I'm waiting until I finish losing the weight I need to burn off of me before I cut the seat material in the Corvette.

I raised the front of the seat mounts @ 1/2" with spacer so it hit the bottom of my thighs. Made a huge difference in driving comfort. 6'7", 216 lbs. No real issue with my head hitting and I keep the seat off the quarter panel, but within 1/2".

Raising a seat is EZ/PZ. Lowering it is a different matter, more complicated. First you want to check where the seat back is hitting the rear quarter panel; and try to determine what, if any, modifications can be made to this panel so as to provide more room.
Actual seat lowering can probably be done. I know there is a kit for such with the 2013 Dodge Viper at about $500. Basically the kit removes the fore/aft movement of the seat for a parmanent-fixed location. I suspect the kit has you removing much of the seat adjustment hardware. This will take some reverse engineering, but really should not be all that difficult. Whatever, you will be a "pioneer" in this venture. Suggest you start with the purchase of a lower seat frame. Not cheap, but it will give you a good idea just were you can cut height.
https://www.ebay.com/itm/2007-JAGUAR...4AAOSwIGJaRT0Z

Do you have room between your knees and the dash?

As you scoot the seat closer you can angle the back farther.

I do not have a lot of space between the dash and my knees, and this lets me put the back where I want it.

I guess I'm missing the problem here. I'm 6'3" at 230lbs and don't have a room problem. No head room issues with the top down but at least 2" with the top up. Have the heated/cooled seats and tilted back to be about 1/2" clearance with the side panel. Seat is bottomed out with the front raised a touch. I find a 4 hour drive to be comfortable .

The point I tried to make in suggesting purchasing a separate seat frame for modification is simple: retain the stock oem frame for resale. It is a fairly simple matter to exchange seat frames.

Height gets built in different ways.

Then there is height when sitting down.

Chromey, you seem to be satisfied with the extent of the fore/aft seat travel. Sport seats are unlikely to change fore/aft travel. I think you'd be comfortable if your seat could tilt/recline more when the seat is at rearmost position. The "back" of a sport seat may be thinner allowing more recline. But, the test for you is very subjective. Find a Jaguar with XK sport seats and see if they work for you. If they do, then consider sport seats, but I think you will find them very, very expensive and almost impossible to find.
Consider removing the rear panel which now limits your seat recline. Does this help? If so, maybe leave it off during your ownership. Reinstalling it when you sell the Jaguar should take just few minutes. This may be the cheapest solution.

Cee Jay,
Like you, I was about 6'3" but when I had some surgery last year, I was repeatedly measured for the first time in years, and I've lost 3" as I'm now 6'0." At this rate, I'll be shorter than my 5'7" son in a few years. I'm a shrimp now and getting smaller by the minute. I also wish we could recline our seats to lay back.

The bright side is you'll fit the car better...