The only saving grace for your opponents is that they don't buff themselves, but you'll figure out a way around that easily, I have faith in you
You can use Maximum Belt (PRE 117) as your Ace Spec to bring that damage up to 330, which is a lot better of a number, but this is still not an excellent solution that you can consistently use
Hammer of Nazahn might even be a little stronger, since it occasionally gets around equip costs
If you want to , harmonize also allows you to tap one of your creatures to reduce said alternative cost ( strictly better than flashback!) As a drawback, you have to exile the harmonize spell as soon as it exits the stack (exactly like flashback)
24 OP-09 Series Packs
Adding counters, recursion pieces, and ways to protect your combo will only serve to help you in the long run