Built a detached garage in backyard, the underground line only allowed for 6-3 wiring. The 6-3 had to travel 110 feet to get to the sub panel in the garage.

The garage is an 800 sq ft garage with a loft above it. The loft will eventually be converted into a small apartment. I plan on having a electric water heater, range, washer and dryer etc. (small ones)

How much problems do, if any do you think I may have with this 125A panel with 6-3 on a 50 amp breaker at the main.

ALSO- how many wires can I run through a single hole in the studs. To save time and to make it easier, I ran 5 lines, 4- 14-2 and 1 12-2 wire. This travel under two windows about 10-15 feet.

Thank you
Dennis

First the references :

List 1 : wire-gauges (http://www.engineeringtoolbox.com/wire-gauges-d_419.html)

List 2 : amps-wire gauge (http://www.engineeringtoolbox.com/amps-wire-gauge-d_730.html)

8 AWG may carry a maximum of 50 Amps as part of a 3 conductor cable. But that is based on short length.
The distance is 110 feet. Add for internal wiring 30 feet. Total wiring length=140 feet from panel to panel.
You want to feed from a 50 Amp breaker. So see list 2 : 50 Amps requires above 90 feet 4/0 wiring.
Wire 4/0 diameter = 12 mm / Cable 3 x 4/0 = 25 mm = 1". So the cable to use = 3 x 4/0 AWG with a 1" diameter.
That is the LEGAL SPECIFIED REQUIREMENT.
If that cable fits than use that. Buy aluminum core cable to save costs.
As you go underground you either have to install 2" conduit for 3 wires of 4/0 , or install a 1" 3 x 4/0 armored cable.
Success!
;)

Clarification:
This wiring has already been done. Im now attempting to figure out what I can accomplish with the wiring with the previously stated tasks.

And will I have any problems with the 5 wires ran through the one hole, thanks

Clarification:
This wiring has already been done. Im now attempting to figure out what I can accomplish with the wiring with the previously stated tasks.
And will I have any problems with the 5 wires ran thru the one hole, thanks

An AWG 6 wire is rated max. 50 Amps.
An electric water heater draws up to 20 Amps.
A washer up to 26 Amps.
A dryer up to 30 Amps.
Your AWG 6 wiring is insufficient for the appliances you intend to use.
.
"how many wires can I run thru a single hole in the studs".
Depends on how big that single hole is. You know. I don't ...
And what is a "stud"? A hole in a bolt or cover? You mean of a distribution box? Measure the hole and provide more detailed information, please.
AWG 6 wire= 4.115 mm or 0.17" in diameter.

:)

the hole is a 1 inch in diameter and Im not worried if they will fit but rather if there is a problem with too many wire put together. The "stud" is referring to the 2x4s the hold the garage up.