the ones i use are 41mm square unistrut square washers.
about 20p each from city electrical or any other wholesaler.
i slot the 10mm hole then cut that side down to 30mm.
so the overall dimensions are 30mmx41mmx5mm thick with 10mm hole (slot) pukka heavy duty steel to support my lardy butt without buckling.
raises the back end approx 15mm - 3/4" ish
as in the pic i posted tother day
the pooey ones on sale on ebay for a fiver plus p&p are 25mm x 15mm x about 2mm, 10mm hole and made of soft ally.
you would probably need 3 of them to make any difference to the handling.
heres another pic off v2demon - a bit smaller than mine, more or less same size as the ebay ones but thicker.
