i suggest to go for SG.
I leveled up in thors, effectively with mediocre gears.
only good gear was DPT book.
just asumptio urself, and have lot of vits, u will survive kasa's attack !
i kill like 4 or 5 and then die. pretty much dead without asumptio
but still, exp is worth is. 250k base exp and 170k job exp

kill two kasas, and u reach almost same exp as lh3
for odins, its even more easier. U can survive a lot with ESL. just avoid brown skeggs, if u r so scared

my initial gears
+5 magni cap / erudite ribbon - for 80sp more
+5 odins blessing pasana - thor / Adventerous suit with angeling armor - odins ( i bought at cheap price, so no complaints )
+7 stone buckler of royal guard
+7 devi muff
+7 eddga shoes - just for 8% more hp. U can also go for sleips[0] or DL sleips for more HP and SP
Hell poodle ring + SR ring ( but with kaahi, u dont need these. Just have any luck increasing gears or dex gears)
+10 DPT book
with upgrades, i have these new

+5 mask of ifrit kaho
+10 DPA book ( abyssmal knight)
pretty much enuf

i also have a morrigane belt + crit ring, for more crit .. just in case it affects heat
u just need patience in killing stuff initially. Once u get Miracle mode, ur damage goes twice and u make 1k+ damage without even a celeb / meg
with meg and celeb u shud be making 1.5k+ to 2k+
pretty much sums up a lot

Champs are awesome in Solo, MvP, WoE, PvP. So, in case u need a all purpose character, make a champ. Ur investment pretty much starts at 300mil+ and takes way lot more time to gain that much back

SG's are cheap, effective and faster !
Regarding DG, U can also Solo in DG with GTB i guess. But i dont know how kaahi works along with GTB. Other than that, its likely possible u will get a rare every hour

. That is like atleast 6mil+ for cursed hand/diab ring and 15mil+ for ventaus/diab mant