Run stand wiring

Hi all, I'm almost done building a run stand.
2 wiring questions, wait, 3.
#1 I noticed there are no fuses in any of the circuits. Should that be a concern?
Only elec.gauge(fed 12v from ign switch)is coolant temp.
Oil psi is mechanical, tach is elec(obviously).
#2. See pic of my hand drawn schematic, that's our 67 engine bay with 70+ square back alt and vr. There is a 3,wire splice, pointing at it withwire(blue from vr, blue from alt and lite blue with yellow trace from ecu), these connect to run side of ballast resistor.
Can these
all be connected together on the connector at the ballast?
Also alternator will be installed to keep belt tight on wp and crank.
#3 Any issues hooking it up electrically(fld from vr, fld from BR and black from starter relay.
Thanks
Steve
****EDIT*** Question #2, there are actually 4 wires that connect to "each other" the one I forgot to mention is the 16ga dark blue with tracer from ign #1 on switch to "N" on bulkhead, which leads to ballast resistor on "run";side(and the 3 other wires).
Thanks

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Just install an inline fuse and be done with it. Below is a video of a guy explaining it.