NO, not necessary at this stage.
The following assumes, from what you wrote, that you have no glassing or composites building experience:
Vacuum bagging is good for more refined control of resin:fiber ratios and keeping weight down.
Can help with shaping also, by holding board to rocker table without extra jigs or fastening.
Unless your boards are going to weigh well under 2kg before glassing, it is probably not worth it to vacuum bag them in my opinion. The amount of weight saved is not that great. You should probably shoot for getting a 3kg board rather than the 4kg board it would be easy to make as a first-timer. Vacuum bagging, refined glassing, carefully tapered lightweight cores, carbon, etc are techniques to use to get you from 3kg builds to 2.5 or less. Each of these more advanced elements or techniques may save, on its own, a few hundred grams, or less. Putting it all together is what gives the superior result. Usually this requires experience.
My opinion is that you should first learn what are the basics and the mistakes to avoid, that will get you to a 3kg, useful board. Then you move on to awesome light boards.
Any extra $ spent on vac bag equipment could be put into cores, glass and epoxy instead, giving you more practice and experience.
If you have 4 boards that are significantly different in size and shape, finish them the same way and learn the differences. Then modify them and ride some more, etc. Keep a log of what you do.
Or, if you have 4 cores that are similar at this point, finish them in different ways to evaluate the differences in tapering, rails, amount and orientation of glass, fin position, etc.
PS: if you want to buy something, buy a powerplane, makes short work of tapering cores. Let the chips fly!
Last edited by BWD
on Wed Feb 12, 2014 7:08 pm, edited 2 times in total.