You will have long grain to long grain so a good glue joint will be stronger than the wood. You can use the biscuits for allignment.
Just make your slots extra long to allow for some registration wiggle room. Norm used this method in one of his projects but went around the cabinet with a slot cutter bit in his router and installed the biscuits in the face frame. I think you could just double cut the slots with the biscuit cutter and be OK.
You can use the biscuits for allignment.
Biscuits have some play along their length, but are rigid along their width. So, if you have a face frame with rails and stiles, and put biscuits in both...the rail biscuits move left-right but not up-down, and the stile biscuits move up-down but not left-right. The end result is a tight fit that [STRIKE]requires extreme pounding with a deadblow hammer until you remove that one stray biscuit that doesn't quite seat because you sneezed when you cut the slot and holy cow the glue is setting would you PLEASE get into place[/STRIKE] is perfectly aligned.i must be missing something ............. every biscuit i have ever used left some play in the alignment that was at least as much as you can reasonably expect out of pocket holes with minimal clamping so how exactly does this help? dowels i could see as an alignment helper but biscuits ???? like i said i must be missing something