No problem doing it with chisels as you clearly want to learn the process and seem to enjoy hand tools more than power tools. However, don't fall for the chisel is faster argument. I do lose tenon joinery for the most part. Now it is with Festool Domino, before it was with a Wood Rat or Router Boss. I am doing this as a hobby and there is no way Paul Sellers (I really like him for other reasons), or any other pro can cut 20 mortises faster with a chisel than I can do 40 of them with the power tools I have. I use hand tools too, just not for mortising.