RE: tuning an Evo 74L 05 model
Most tuning details you discuss are mostly about personal preference. That goes for example for boom height, mast track and foot straps. I personally don't change my boom height when switching between trad and EVO, but know some poeple think its easier to make the EVO work if you raise your boom a bit. Ragarding mast foot, I personally run it at around 130-132cm from the tail. Ususally I don't change my mast foot when using a bigger sail. As for straps, I run my back strap in the rear hole and adjust my front straps for a preferred spread which on the EVO 74 06 was in the mid position. The 05 has, I think, three posisions both front and rear and then I run bot straps in the middle. But again, lots of personal preference here.
Regarding fins, I know of the Selact brand, but I have no personal experience. I think they have a bunch of different wave fins. If the 23.5 fin is kind of traditional in shape (fairly wide base etc), I think its OK with a 5.7 but may be a bg big with 5.0. The Drake fins sail small for their stated depth, but for 5.0 and 4.5 I think the 22 is the best bet. I think most poeple will find the 21 a bit small unless the conditions are ideal.
Finally, sailing style. The EVOs in general and the 74 in particular is very easy to go vertical on. When waves are small and slow, there is really not much to think about. When wave riding speed increases (faster, bigger waves) its often good to take som care and let the board settle into the turn before cranking it down. As you say, mast foot pressure is key here. One way to do is is that as you drop in, you start the turn initiation by pushing down a bit on the mast foot. This settels the board on its front rail. After that you can start teh actual turn. For a drawn out turns, just keep this forward presure on. If you want to go vert some time in the turn, you don't have to add as much turning force as on most trads. Raqther you just release front foot and mast foot pressure, you easily steer the board on the back foot.
As for the top turn. Anything involving hitting the lip comes pretty natural on the EVO. Carving turns on clean waves is also easy as long as speed is not too high. When this typs of turn at higher riding speeds you have to pay a lot of attention to setting up the turn right. This is where EVOs are more difficult than many trads. But if you take care to sheet out in time, move your hands forwards, and settle the board on its new cutback rail before fully committing, you can still pull it off. Some people feel the EVOs prefers to slide on the top turn. Of course if mght be nice to let the tail break out now and then, but its also good to be able to carve though this type of turn, and with the right setup it works great.
Hope this helps. Ask again if you have more questions.