should it be a little harder to start my truck after advancing the timing to around 16.5?

 

Mine start up just a hair slower with timing set at 16°.
If you are having to crank more than a few seconds it could be the timing was advanced more than it was supposed to be, easy mistake to make especially when tightening the nut.
Once over about 18° starting gets harder and harder.

 

well the cranking time is the same but when it kicks over and sounds like its starting it just dies. it doesn't necessarily take longer in the cranking part of the sequence.

 

Mine doesn't turn over one full rev before it fires if you just rest your foot on the fuel pedal.. off the pedal, it only cranks a couple of times..

What's your idle, once warmed up?

 

about 700-800

 

Sounds a little low, unless that's in gear with the A/C on.

Mine sit on the line just under 1000rpm in neutral, A/C off
750 (line between 500 and 1000, since they aren't in 100rpm increments) with the A/C on and in gear.

Does this help?