Hatch notch

I recall seeing a post on this and i plan on using the same technique where im cutting my notch after the hatch is built witch is now.
Ill use a rebate bit then flush trim to cut it out but was hoping to get some ideas on notch size and seal size people are using.
Im aware the generic benroy calls for 3/8 notch witch basicly equates to 10mm .
My hatch skin is only 3mm ply that will be covered in PMF prior to being skinned with aluminium and i have edge trim to go on witch will reduce the notch size,ill try to do a mock up.
so lets see some pics or ideas!
Cheers in advance
Ill use a rebate bit then flush trim to cut it out but was hoping to get some ideas on notch size and seal size people are using.
Im aware the generic benroy calls for 3/8 notch witch basicly equates to 10mm .
My hatch skin is only 3mm ply that will be covered in PMF prior to being skinned with aluminium and i have edge trim to go on witch will reduce the notch size,ill try to do a mock up.
so lets see some pics or ideas!
Cheers in advance