I would check with VPI to see if they have a different counterweight. I have a Basis 'table/arm, and I had to order a different counterweight for heavier cartridges, like the Dynavector XV-1s, from Basis. Hopefully you get a chance to listen to the 4D at it's best. I, myself, wouldn't feel comfortable attaching a coin to the tonearm.
Currently I'm running a ZYX 4D-X SB2 and I have to say that I am very impressed. I like the 4D-X better than my previous UNIverse-S. The UNIverse had a sweeter midrange, but the 4D has better resolution and extension. Some of this may be due to the silver vs. the copper coils.
Cheers,
John