The TB Size for any engine will be determined by the
HP Requirements made by the owner of the car.
Engine CID, Engine RPM, will ultimately determine the
'Required' size of any orifice within the induction system.
So if your going to shift that engine having an 4" stroke
at about 6800 rpm, it is going to require a larger TB
than if the engine had a 3.622" stroke at the same
engine rpm, as the Piston CFM Demand will be higher
at any engine rpm with the 4" stroke.
But with these engines the blower is going to put a 'Cap'
on any engine having a Piston CFM 'Demand' exceeding
about 1150 cfm, as that's about what a Stock 1.9L Blower
Ported blowers will supply around 1250 cfm. . . Depending!
That's worth about 60 fwHP, maybe another 10 - 15 fwHP
depending on who ports and tunes.
-with the stock blower-
With your compression ratio I would stay with the 87mm TB,
maybe a 90mm TB, and move over to E85.
That is going to solve two issues.
First, the Octane Level will be increased.
Albeit mainly just the RON, but it still helps for short bursts.
Second, E85 is an Oxygenated Fuel and will deliver oxygen
to the cylinder, around the TB, as it is moved into the cylinder
via the fuel pumps / injectors.
If you go with a ported blower, and your engine rpm is
sufficient to generate a Piston CFM Demand to require
more air than the smaller TB's will deliver, then you
can move up to the 102mm TB.
So, it all comes down to your HP Demands, as well
as sufficient Piston CFM Demand. Your job is to
define the above and then fit the engine accordingly..
Now, let's end this by restating . . .
"Engine CID, Engine RPM, will ultimately determine the
'Required' size of any orifice within the induction system."
None of the above can be determined without understanding
if the cylinder head flow and camshaft are sufficient for your
intended 'Peak HP' engine rpm. .