use the viper gasket. the srx water rail doesnt work, you need to block off one hose, remove the thermostat, then it interferes with the coul below the headlight. if your impatient and it is the last ride of the year and you have been up all night making your srx pipes fit in your viper and your friends are waiting to go riding on you, you can cut it and use it.
you need a mega power water rail, you can also have someone weld two srx water rails together
those heads with a gasket will probly give you about 120lbs compression. for what your doing, using 1 layer will give you about 130lbs. i wouldnt go any tighter on a stock head for trail riding