Headgasket is not hard but you have to be dead precise. Alloy castings need to be treated with care, so grab yourself a rubber mallet jic, use timber to sit it on when it comes off, and follow the rules/procedure to a tee.
I've hear people using wire etc, but when it comes to it, after investing all that love, money and time you don't want to think you are a tooth out, or screw up and calc it all out and **** yourself when the time comes to hit the key... I would do it with the tool, they come up on ebay or can be bought from shops that do engine work and sell parts, just look around. Not too expensive (see the one below), unless you want a multi-purpose one that does more engine types. Just sell it off cheap after you're done with it. E.g.
Camshaft alignment tool set for M42/M44/M50/M52/M54/M56/S50US/S52US engines
Product number: B-A1033
(Direct link to B-A1033)