hilly said..
Mine is 400mm so actually pretty consistent. Longer boards have the mast tracks further forward and the deck pad further forward. Slight variation is with the location of the deck grip on the hump. Mine is not fully up the hump so the 50mm difference between mast track and deck pad (350/400) should be closer to 30mm like yours.
If the hump was 3cm further forward that would resolve all the issues for me as my back foot could be on the inside of the recess and still not be behind the mast.
Its not the biggest issue but would be perfection if i could slide the foot back to hit the bump for pumping up, then bring it forward of the mast once i start the run.