Nodowa is a good option as stated. After you can synth Darksteel Picks which are almost break even if you NPC and buy darksteel ores at 5-6k range then craft your own materials. After that, it will get quite costly. You will likely spend 1-2 million on troll bronze ingots by turning them into sheets. Getting other crafters to craft the ingot for you is a way to save gil, you'd probably end up with an overall cost of HQ to break around 3-4k per ingot if you had a crafter help you make the ingot however the ingot desynth recipe is higher than the sheet and at low levels you will likely nonstop fail. Also, high level crafters seeing that you want to go 100 will be hesitant to craft the ingots for you, especially since they would need to spend countless hours to craft tons of stacks of ingots. I think it took around 30 stacks for me to get through that phase. If you consider have no outside help with desynth that means you are sitting at something around a 2 mil loss. Sheets can be used for Januwiyah-1 shields which is supposedly the bridge from adaman ingots to imperial wootz ingots. However, the shield supply is next to non-existent for the serious crafter. You will have to start stock piling as soon as you see it on AH letting it rot in your mog house till you can use it. Unless you have a bunch of mules that could take up space you would need to farm up other items to keep your gil flowing regularly. However, with the way things are, you also have to consider that each imperial wootz ingot break will cost you over a mil. It requires a variety of materials of which is K. ore x2 which last sale was 500k each. I suggest for that route to farm your own but you would likely need tons of Imperial standing for ISNM3000.
Bottom line: if you are entering it thinking it will earn you a big pay day at 100, you may want to just stop smithing at 60 and keep it a sub craft. This is by no means a cheap craft to level and there isn't a super strong pay day at the end. One of the biggest problems as I see it is armors take 1 inventory slot regardless aka they don't stack so you are forced to do ingots typically which can be costly, also the armors typically don't sell fast with the exception of a few, which are only profitable as HQ, which is a really low rate.