Here's what I do.
        After I have sealed the boat with a couple of coats of epoxy resin, I give the boat a sand to knock down any epoxy lumps and to provide a key for any fillers. Large holes to fill ( shouldn't be any) and any tape edge transitions are filled with epoxy resin and filler powder ( I use WEST resin and 410 Microlight filler.)
Once this is sanded back I spray the entire boat with Altex no 2 High build surfacer which is essentially epoxy fairing compound that you can spray on (it can also be trowelled or brushed). International and Awlgrip also make similar products. The beauty of this product is that it's hardness is consistent. It is very difficult to mix up a batch of epoxy resin and filler to the precise consistency of the previous batch and this can lead to differences in hardness of the fillers. If you have a hard patch of filler (resin rich) next to a less hard, (filler powder rich) mix and then try to sand them both the softer area will get scrubbed out first and you will chase your tail trying to get the boat fair. The Altex #2 is beautiful to sand and fills fibreglass weave really well to leave a lovely fair surface.

        Once the #2 is sanded (most is sanded off) it needs to be sealed so there is no "shadowing" of the bog into the topcoats. Here you can use the grey primer for single pack systems or the Altex #3 undercoat for a two pack job. With either a single or 2 pack system, we apply 3 coats of undercoat. Normally 3 coats is enough but if after sanding the hull back I have a lot of "grey areas" showing through, I will add another coat or two to provide an even white surface. This helps lighter topcoat colours achieve and even colour with minimal coats.

       When applying the undercoat, I generally spray as it achieves a really even surface but the same can be achieved using the roll and tip method. Try and apply the undercoat as smooth as possible as it will save lots of sanding. Finally after all the prep it is time for the topcoats. The thing to remember is that your topcoats will not hide an unfair surface or fill holes.
 
       Once the undercoat is sanded and the boat is vaccumed off, I give the boat a couple of wipe downs with a silicon and wax remover. This is available from hardware stores, super cheap auto, repco etc. This ensures that the hull is clean and there is no contamination left on the hull that could affect the topcoat. Next step is to tack rag the hull to remove any final dust and then paint. Sounds like a lot of work but it is worth it.
 
      When applying topcoats, you can brush or spray. The roll and tip method works well for both single and two pack systems but if you are going to do it with two pack, ensure that you have the right converter for brushing which allows the brush marks to flow out. I generally use high density foam rollers (Uni Pro brand) and high density foam brushes (Jen Poly Brand)when rolling and tipping.

     With the two pack system, you can also get a gloss reducer or matting agent to de-gloss the paint. There is nothing worse that having the inside of your boat in full gloss as the glare is terrible. I normally use a satin to semi gloss on the inside of the boat and a semi gloss on the outside. Wooden boats generally don't look good with that wet look high gloss in my opinion.