Assuming blanks made from the same materials, manufacturer, similar weights and powers, which blank would have the lighter weight tip end, and balance closer to the butt? A fast action blank, or a moderate/moderate fast?

I'm not talking about power or about balancing the finished rod, I'm talking about actual, physical weight.

I also assume a shorter rod of similar power will also feel less "tip heavy"; a 6'6" ML Mag bass will feel less tip heavy than a 7" Mag Bass (assuming the rods are built identical, with identical components and placement)?

For example, here are the specs on two blanks I could use for a particular technique:

RX8 - XSB842-TC 7'0" 1 8-14 1/4 - 5/8 oz. 0.455 4.5 Fast 1.41oz.

RX8 -XP842 7'0" 1 6-12lb 1/4-1/2oz 0.405 4.50 Mod-Fast 1.35 oz

Which of those two would be less tip heavy?

I got back into rod building after a long hiatus to build a more sensitive rod, But was surprised at the huge difference in perceived tip-weight between a light high modulus rod a an IM. So now I'd like to play around with building lighter rods.

The further out towards the tip you put any weight, the more out of balance it's going to feel in your hand. Assuming the power rating is for mid and butt power, which is where the power is located, then the faster action version will have less material out near the tip resulting in a blank that balances further towards the butt.

..............

Gary,
Though related rod action and weight distribution are not the same.
A rod may have a fast action and still feel tip heavy through the application of a small butt dia with little taper.
Likewise a slow action rod can seem tip light if a lot of taper is placed in the butt section.
Weight distribution is what I believe you are looking for in that it determines how close the blank center of mass is to the angler's hand.
Rod action and weight distribution are a function of taper design.
The best tool I've found to determine weight distribution, has nothing to do with the descriptions found in marketing jargon rather is the measurement of the bare blank for the characteristics you wish to find.

Eugene Moore