Velbon Macro Focus rail, X-Y axis gear driven with lockdowns on both axes.
Gives ~1 1/4" side to side and ~3 1/2" fore & aft adjustment. Certainly heavy enough for any 35mm camera or most Medium Format.
I'm not sure about The 6X8 Fuji, but is OK with RB67.
$60.00 includes shipping to US address. International at actual cost.
Paypal Preferrred-NO FEES to buyer.