Roller cam newbie Once you start going down the rabbit hole!

Alright, it seems I have a heck of a lot to learn. Valve stem positive seals - Do we need to machine heads for this? Valve springs for camshafts, what pushes the need for springs, the duration, lift or rpm.?
I am looking at getting a roller cam with these specs, DUR @ .050 218INT/224EXH Intake lift .535 Exhaust lift .531 (1.5 Ratio). So I will need a spring upgrade I was going to get Melling 466463 the specs say coil bind is at 1.025. So .535 X 1.5 = .8025 lift for coil bind.? (But the way of my thinking is if the lift is .535 with 1.5 Rockers then is that not the max lift? & if so a coil bind of 1.025 seems EXTREME!) Am I reading/doing this correct? Or are the other specs like installed load & height (112 @ 1.687) & open load and height (290 @ 1.187) factor into the math of figuring out maximum lift for these springs? Also will I need positive valve stem seals. Will I need to machine the heads for these valve springs? I was also looking at Hughes 1110P springs. Anyone using the Hughes or Melling springs I mentioned? If so what lift are you running and did you need to do any additional machine work for these springs? Thanks guys and gals.