new to sewing with machine

[new to sewing with machine]

here are photos of back

[new to sewing with machine]

i just bought a ga5-1 same as cowboy 105 i think  and having few issues ,1st is that feed dogs destroy my veg tan also 

not sure how to get tension correct seems like i am running top tension way to tight so it does not leave loops at bottom

maybe i should back off lower tension on bobbin and start over on top tension? i am using 277 tread on 8oz veg tan 2 layers

for holsters. i may have ti go back to hand sewing i  hope i didnt waste my money on machine 

please offer advise 

 

thanks