The part numbers for your maxspeed coilover should be 0206-G-na-vg2 , yours should have front spring rating of 7KG/mm and the rears 6kg/mm, which is near enough to give you a firm enough ride once adjusted properly.
Like SDate42 said previously, you sure have a long shaft between base and shock mount, looking at your car side on, you should have at the very least, another 11/2 -2 inches of adjustment minimum.
On the positive side the coilover springs will settle down about 5-7 mm over time, but still you should have more adjustment then what you have.
On the next model up, the CJ they are rated at 9kg/mm front and 6kg/mm rear, so rears are the same rating. Also on the CJ variant the coils have numbers in white on them, which reads 70-5-160-6, Not sure how maxspeed mark there coils, as some manufactures vary, sometimes the 4 letters may read as
- overall length
- inner diameter-70
- coil wire thickness
- spring rating, in this case it appears that only some of this could be right, that is 70mm inner diameter and 6meaning 6KG, the other 2 don't follow and usual order.
if you haven't sorted it yet, check out what is written on the coils of your springs, and while the wheel is off, take a pic as well, lowered on axle stand if possible.
Joshua Quidlat idea of shortening and welding was a good one, thats one way to do it, the point is though if you buy these to fit a ch then you shouldnt have to, never heard of this before except when people want to swap over coilovers to different makes I've had pedders extreme and BC coilovers, and this was never a problem, its a strange one, thats for sure.