First off, I can only assume that there are dozens, if not hundreds of posts related to this topic.

Therefore, I will make this to the point.

I want to build a roll (moving up one level each month, up to $600 NL full ring, and perhaps beyond)

I will start at $4 NL.

My only question is this;

Would it be easier to build if I buy in for 50BB or 100BB (with 20 buyins total)

It seems fairly straightforward that 50BB would be better, I'll just play tighter (I will be 4-tabling at most), but I concede that I could be missing something fundamental...just don't know what.

Thanks

How much are you starting with?

I'd be surprised if you'd be able to move up one level a month. You'd have to put in some sick volume.

I'll be depositing $50-$80 with a buyin of either $2 or $4 at (.02/.04 NL)

I think it can be done, certainly for the lower levels.

What I neglected to mention was that I will be playing tournaments as well. So, say I win or have a nice cash, I will keep that money in my account (even if it makes me incredibly overolled for the level I'm at), and wait until the end of the month to see if I'm ahead at my current level. If I do show a positive profit from my current level I would then move up to the next level. and repeat, and repeat, month after month, etc.

the stickies and search function are your friends

I think, above BR management, you will need to learn a lot about poker in order to progress at the speed you want. Your BR will be ready for the next level long before you are.

Alright, make that 2 months to a level

<--------working on reading all the stickies

I think it's not the best way to plan your level up like that. First you need to develop your skills and try to beat your current level with a decent winrate over a large sample size before considering to move up.
The second thing is that 50bb poker and 100bb poker are completely different and you should start by learning 100bb poker as there is much more content available on the internet.

I see a lot of players buying in for 50bb who don't know how to adjust their game, and I think it really hurts their performance. When you are 50bb deep, you can't call raises with speculative hands, since you don't have implied odds. You also have to be willing to stack off more often with top pair, since the SPR is going to be so much lower. You also have to be able to read your opponents to see how they respond to your stack size. Some will go aggromonkey on you because they don't have to fear losing a whole stack. Others will be reluctant to proceed past the flop, since they know that you are committing yourself more easily.

If you can make these adjustments, you should be able to play 50bb profitably, albeit not as profitably as you should be able to play 100bb, since the amount you can win with your big hands is capped at your stack size. If you cannot make these adjustments, you will be yet another half-stacked donk who calls off large portions of his chips chasing sets and draws and who bloats pots only to fold them at the end, and thinks he is somehow saving money by playing less than 100bb.

100 bb it is, thanks