I have checked this with the manufacterer, so please be patient...
But a 6 ch driver starts me thinking of a Hex moduleinstead of quad
Without the use of a telescope I think a beam of 3,8mm x 3,8mm x 0,8mrad should be possible with a hex module.
3,5mm or even 4mm beam is still very acceptable I think.
PS. on my webshop you can also find waveplates. with these optics you can turn the polarisation of beam, so no need for stacking the beams vertical anymore.