Listen, 1-99 in lazy mode can be done in 1-2 weeks...stop worrie about lvl 1 buffs.
I dont think you fully understand how important is iss in a party...he do buffs but he do also debuffs, at,heal,ress,etc, 40% less def for mobs its something important. Its not simple to play ISS... You have to know every aspect of game.
I think you should take Nuky advice and focus on a DD...Also you are on a wrong path, I mean you even not hit lvl 103(you are still considered low lvl, you need 105) and you think about dualclass .
Im telling you again, Tyrr Duelist is not good...not good in pve, not good in pvp. Worth play only as main class for obvious reasons. You can choose any fast lvl 1-85 dualclass and then change it with what you like for 100 mil adena...
Regarding gear demanding 85-99....
-2 sa full element bless apo or better
-2 crti rings
-octavis neck
-talismans(abundance,longing,faction,anakim,venir)
-x15 lvl5 dyes
-str+patack/or what its suitable for you head acc
-+6 bless set full element
-any good item you can get
here:work with 2h also.... https://l2wiki.com/Superior_Sword/Blunt_Weapon_Mastery_-_Iss_Hierophant