Hey again,
 
So,
 
I have my 3 avi's with 3 seperate [gemheads] which I can now move around the [gemwin].  Cool.
 
Could someone enlighten me towards the relationships between [translate] and [rectangle] please?
 
I would like to keep the original aspect ratios for the 3 avi's.  Avi 1 is an odd shape  - w432 h768 - (it's approximately half of my laptop desktop recorded with RecordMyDesktop) and avi 2&3 are recorded off bog-standard camera's, so are 320x240. The larger file is on the left of my gemwindow with the 2 other avi's to the right, one above the other.  I have added the widths of film 1 and film 2 with little borders which gives [dimen 762 768(.  I can move the files around and get an approximate fit moving between each [translate] and [rectangle] but I get the feeling there is a more rigorous approach.
 
Apologies in advance if I have missed something in the helpfiles or various tutorials but I can't seem to find the info I'm looking for.
 
Best wishes,
 
Julian