Gluing paperbacked veneer back to back

Hi, I’m trying to glue some paperbacked veneer back to back, that is the paper back of one sheet glued to the paper back of another sheet. Reason being I need veneer sheet stock about 40-50 mils, and the only good selection of veneers I have been able to find are either ~20 mil thick, or in some cases 30-35 mil (still not thick enough and my application is thickness critical). See this post for more background info http://lumberjocks.com/topics/37256#reply-426589 – I’ll add the reason for having the (same) wood on the back side of my sheet is because I laser engrave shallow reliefs into them, and I’d rather do this into wood as opposed to a plastic substrate or a paper backing of a second veneer.

So, are there any implications I need to be aware of before I attempt this and buy equipment and supplies? For example, I was going to use a vacuum bag with this glue – http://www.veneersupplies.com/products/Better-Bond-Titan-DX-Premium-Contact-Cement.html – however it specifically says that application needs to be done with a scraper for adequate pressure (not a roller, does not mention one way or the other with vacuum press). If I’m doing several boards approximately 24” x 12” will it be very time consuming or exhausting to manually press them together if a vacuum bag will not work for this type of glue? Should I consider a different type of glue altogether?

Last consideration I can think of is whether to align the grain or go perpendicular. I like the idea of added rigidity from a perpendicular ply, but I also need to consider stability. Since I am not applying the veneer to a relatively rigid substrate like plywood or MDF, I need to achieve maximum stability of the sheet on it’s own. I realize I won’t acheive zero warpage, but I want to minimize it. I also would like to minimize the amount of cross-grain expansion and contraction of the wood due to surrounding environment the part is in. Seems that a perpendicular construction would aid in this.

Any and all input would be much appreciated!