It's pretty normal to scribe them to the floor in kitchens I'm making. Same with skirting boards.
Place the plinth on the floor and mark the undulations, cut that with a jigsaw. Now it's scribed to the floor cut a straight line to match the line of the bottom of the cupboards. Allow a little wiggle room.
I like to add the special plastic strip under the plinth material as it stops them sucking up moisture and covers any ragged edges from the jigsaw.
It's pretty normal to scribe them to the floor in kitchens I'm making. Same with skirting boards.
Place the plinth on the floor and mark the undulations, cut that with a jigsaw. Now it's scribed to the floor cut a straight line to match the line of the bottom of the cupboards. Allow a little wiggle room.
I like to add the special plastic strip under the plinth material as it stops them sucking up moisture and covers any ragged edges from the jigsaw.
Other retailers are available.
https://www.amazon.co.uk/Lengths-Kitchen-Sealing-18-19mm-Thickness/dp/B06ZYNGHYT/ref=asc_df_B06ZYNGHYT/?tag=googshopuk-21&linkCode=df0&hvadid=345527343787&hvpos=&hvnetw=g&hvrand=7859752397335718289&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9045907&hvtargid=pla-718582239351&psc=1