Question about seatposts and shims

Question about seatposts and shims

Ebikes go fast which means shock-absorbing seatposts and *soft* saddles (e.g. Velo/CCM Mega Gel) are
imho mandatory.

Questions:

1) Is is possible to machine down a shock seatpost from 27.2mm to
2.4mm without compromising safety?

3) Is it true that a shim made from pop can aluminum will be good enough to shim a post from 27.2mm
to 28.6mm?

Thanks for all replies!