ive come to the conclusion that contact sheets are best fit for 11x14 paper, no matter the format. a 35mm 36 exp roll will simply not fit on 8x10 paper, and neither will my 10 6x7 shots from the mamiya. as much as i try saving paper i think making contact sheets on 11x14 is the ebst option.
I use a Patterson Contact Printing Frame 35mm for years and have had no problems. There is even space to enter location of the shots and dev. details.