I am buidling about 35 quarter sawn white oak 4 paneled 1 3/4" wooden 3 ply laminated interior doors and would appreciate any members' suggestions on what size dowels to use. I believe for me that this is the best way to do it, and have never used dowel joinery before. I do have a Jessem doweling jig. It is not the newest one out, but the one that has maximum hole diameter of 3/8". Not sure if this is good or not and hate to buy another jig, but if 3/8" is not good, than I can go 1/2". I doubt for me it is worth going 5/8" diameter. I can go 3/8" and just put in more. I also would like to give a little slack in the hole to the dowel and like to know what is a good overage for the dowels to be made. I usually use loose tenons for joinery but decided in this case to go with dowels. I also thought that using a long special lag-type screw going through top side style into rail and plugging the holes would add extra strength.

Door parts are solid laminated 3 ply styles and rails. I cheated on some parts and just glued in small thickness of solid wood where it will be seen, and used plywood for rest of lamination. Sides and top rails are about 4 3/4" wide. Bottom rail is 3 ply 10" wide. Middle is 8" wide. Verticals are 4 3/4" wide. Any recommendations for each joint is very appreciated on how many to what size suggested, how far apart from edge and from each other, and how long. How much loose fit, which I want to do, should be given, and best glue to use. I have enough parts for about 4 doors made right now except for panels which I plan to install after I install doors, as these are too heavy for me to install alone if all put together at one time.

Also any suggestions on where to buy the dowels would be helpful as well as the best bits to use. I normally use Fisch brad point wood bits, but again, I am looking for experienced answers from guys who do this more than me and any suggestions for ease of build would be very helpful.