Dilemma on crafting gear progression

[Grux]

Dear crafting experts,

I'm new at crafting.
Basically this is what I have at the moment http://ffxiv.ariyala.com/SWFD

I'm trying to get into 2/3 star crafting for my specialists classes and I have no clue where to start.

I'm really looking at minimizing cost - cant afford to do perfect pentamelds like you billionaires.

So, this coming Thursday I will be having 28 red scripts to spare.
I have the option of buying one of the following:
1) RS OH
2) RS Chest

Is RS OH > RS Chest better than the other way round?

How ideal is it aiming for this: http://ffxiv.ariyala.com/SWFE
Takes some time but I'm thinking since I already have the RS MH. I'll go the route of RS OH> RS Chest > RS other body parts.

And I cant stand the fact melding expensive stuff into sub i150 right side.

So, with the new purchase, I'll probably go into 2star crafting - for the i170 right side gears and meld a little here and there while waiting for the full RS left side gears.

Question:
1) Should I go full retard? (following the game plan above) until i reach full left side i180) - for one specialist class.
2) Should I get the i170 class specific left side and meld them instead? Seemed really expensive
3) Should I just get RS MH on all 3 of my specialist classes and just meld the i150 gears?

I'm really looking at minimizing cost while not gimping myself for the future. Not really rushing to craft 3 star immediately. But also cant stand the fact that if I do meld my i150 gears, it will be unusable come future crafts needing higher requirements.

Also another question, whats your speculation on the future of RS i180 gears? Will they be viable for 4stars in the future?

I'm not sure about the 2.0 crafting timeline and was wondering if there is a possibility that you can actually trade in your RS i180 gear and other materials for a higher level equipment.

I mean they cant just let the RS i180 die just like that right?