I do have 7 friction plates but the clutch was originally assembled with a friction plate as the first plate (on the motor side) and that is how I reinstalled it…
When you get the stack complete, the top cover plate should fit [about] halfway into the baskets 'fingers' at the top edge. In the Old days (sic...) with Honda's own plates the top cover plate would be just outside the fingers of the basket, with the top edge of the top cork plate dead-even with the ends of the fingers. That was their precision in assembly, pretty impressive! Today we are getting generic clutch plates that can range between 0.134" and 0.142" thick brand new, so this old rule-of-thumb doesn't fit anymore. The length of the basket's fingers are based on the 0.141" new-cork-thickness spec back then.
One of the finer points to watch for when assembling the stack with modern plates is: the top cork plate's surface should not sit beyond the finger's ends. If it does then the top plate can slowly damage the ends of the basket's fingers. I have seen this several times lately (since about 2005). If it happens, installing one cokr plate from a 550 (0.121" thickness) is enough to resolve it, so I put that one on top.
The later 750 clutch baskets also have the top ends of those fingers notched about 1mm on each side. These are there to fit the special "slope cut" corks plates, whose cork blocks are a parallelogram (or rhombus) shape instead of rectangular. These types of plates are "slipper" plates, designed to slide just a bit when the clutch is dropped too fast, obstensibly to reduce shock to the primary chain. This was/is a Honda engineer's 'saftey blamket' that came from the lowered primary drive ratio (and slightly elevated HP rating) of the post-1974 versions of these engines, like the F0 and later ones.
The point of that last paragraph is: many of these kitbashed bikes today also get kitbashed engine parts. I am currently reminded of this in the K1 engine I am working on now that had no friction plates at all, and a stack of steel plates from a K6/F0 engine with the [in]famous dual-spring steel plate: when assembling the early clutch with this dual-steel-spring plate in the stack you must lose one cork plate (6 total) in order for the stack to fit. When that happens, you must use the thickest new plates like the ones from PartsNmore (0.140"-0.142" new) and avoid use of the steel plates that do not have the checkered faces on them (i.e., smooth steel plates), to prevent slip.