not really....if for example your thru hull fitting is a 1 inch nominal diameter, a 1 inch hole saw should do fine. The wobble from drilling will make the hole slightly bigger....if its a little snug, take a half round file or one of the mini drum sander bits and a Dremel tool and finish it off. When you apply epoxy, its like applying varnish to a table or door at home. The first few minutes of application will be absorbed into the wood and then another coat or two and it will be set....this is done with one mixing in about 10 minutes. If its a foam or solid glass core, it won't absorb much if at all, just seal it and let it set up. Once curing starts and its hard but just a little tacky, put some 5200 sealant in the hole and some on the shaft of the fitting and install it. Tighten it down around 90% of the way and let the sealer set. Clean up the excess sealer while wet. Then give it a final snug and attach the hose using double clamps.
You want the sealer to cure before attaching the hose because sometimes the hoses and barb fittings are so tight that you really have to muscle it on....if you do this while its wet, you'll squeeze out the wanted sealer. You can use this method for any thru hole or self tapping application.
Now go fishing!