Hi essyou35
I'm unfortunately on my second Viper as my DX18 killed the first one along with two other airframes!
My first Viper with ballast built in caused me to have to relocate items after my initial install eventually going from 0mm back to eventually 40+mm back on the CG
The second one "with out factory nose weight"has a T12 in it weighing1500g, 200g heaver than your K100 so should be more inclied to betailheavy than your set up?
Ihavea single JR8511 on elevator and a JR8421 on the rudder, theres not much else behind the CG thats not factory std
All I have "or need"up front is two 2200 Rx lipos and a 3900 ECU lipo andmy CG with gear down and UAT fullworks out at 38mm back from the wing tube "centre"
Its hard to understand why you need any weight at all is to achieve the correct CG?, you have a nice tidy install and I don't see anything out of the ordinary.
I hope you don't end up with or need 16oz up front! the factory originally only fitted 9oz of ballast in the Vipers which is not really a lot in a 20lb+ airframe.
As the Vipers flight envelope has been explored and expanded then its tolerance for a wide range of CG found, I Guss they felt this ballast was no longer needed.
Its a lot easier to add weight to the nose than it was to remove it but I'm sure if you explore your options you will not have to add quite as much as you think.
Here is a pic of the nose weight from my "late" Red-white Viper for your ref, Its all thats left except for a slightly scrached tailplane 