Brad, if you take the seats out (and they are the original types for this model) that tilt forward, you'll notice there's an Angle piece that's bolted on to the runners. From memory, these are about 3" high at the front and about 1-1/4" at the back. You can effectively chop and 1-1/4" off the that angle piece. I'd suggest flatening the very bottom part that has the bolt holes in it, then measuring up that distance you have at the back end of them at both ends, cutting to that line, then folding an angle back in to them so they can be bolted down again.
I'll just add though, they were never a great seat. They didn't last too well and personally, I found them not very comfortable.
I know you were toying with fitting some Cobra Low Back type seats and if that's the look you'd like, then go with something like them. The Cobra Classic's are 19.75" wide in the base, but the Mounting Platform in the Moke is only 33", so you'll not have enough real estate to land 2 of them on.
If you could find a pair of frames from the 68 - 71 model Moke, they are 'Low Back'. Originally they were made as a 'Sling Back' which looks like the old school beach chair. Many in our Club had these frames retrimmed to something very similar in appearance to the Cobra Classic. The 72 to 79 Base Model Mokes had a similar seat frame and these too could easily be done in the same way. They did have a bolt on head rest that can be removed and the mounting point ground off.
Another option here maybe to obtain a pair of early UK Mini Moke Seats and have them trimmed. Original seats you'll never find, but there's a firm making good replicas of them and another firm has them in fibreglass.
I did mean to reply in your last thread, that I have Mazda MX-5 Seats. They are a High Back, so possibly not what you are after. They can be fitted to sit a little lower than the stock seat, though, it'll be a bit of a battle. Personally, I've found these to be the most comfortable seat I have anywhere (including the lounge room), I have sat in them for weeks on end, day after day and never had a comfort issue with them. I don't have a good back and can be in pain from poor seats, but I can't recommend these highly enough. As a bonus, in the Head Rests, they have speakers (or a cavity for them) which places the speakers nearer to your ears. I find that I don't need to crank it up much to hear from them over the road noise.
Mokes are very hard to find alternative seats for due to there not being much room to fit them.