Transmission Swap Advice

[Marine-58]

Starting to gather parts to swap out the TH400 for a 1994 4L60E. Wanted to add OD before swapping the rear gears to 4.10. Ran across way too good deal on a good tranny that won't need a rebuild. What I'm needing help with is to make sure I have everything before starting the swap. Been researching on the internet and there appears to be a lot of articles on this but each one speaks to a part of what is needed. You guys are much smarter at all this, so hoping for some validation.

To set up the end goal:
72 C10 SWB
383/465hp
12 bolt 3.55 soon to be 4.10
20X8.5wheels
275/60R20 tires
Swapping to 15X14 wheels
29X18.00R15 tires
Rear end - 12 bolt 65" WMS to WMS
Narrowing this to 56 - 58" Pending measurements
Bed is already Tubed
Shifter is a B&M Mega - can be changed to allow for 4 speed by removing a pin.

Here is what I have found out so far:

Torque Converter - going with a 2500 RPM Stall Speed. Not sure of brand yet. $300
Cross Member - needs to be moved but not sure if needing a different one - $10 (Junk Yard)
Driveshaft Yoke - Will find in junk yard - $10
Electrical Speedo or a electric to mechanical conversion $250
Control box - numerous ones to choose from - like the TCI set up, but not sure. $700
Throttle Position Sensor and bracket - ??
Time/Money/Patience... $priceless

All in about $1,300 + TPS and bracket.

This is about all I can derive so far. Will certainly appreciate any and all advice...

Thanks,
David