O ordered a extended Drill from electrical store ( this is flexible the drill bit is 3/8's and the rest of the bit thiner, its used for drilling thru studs behind drywall and then pulling electrical wires )and 3/8 stainless tubing from Amazon
Stainless Steel 316L Welded Annealed Tubing 3/8" OD x .305" ID x .035" Wall 36" Length
Then I drilled paralell from the back thru into the bulkhead with a 3/8 drill, a tiny little bit grinding on the outside and inside hole then cut the tube and pushed it thru, its really snug that way almost does not move, sealed with 5200 quick dry....bam done...
As for the pump opinions differ, I had to drill the same pumps like yours but the wall is very thin and only allows for couple of threads, they say oposite from the other one, but again I know opinions differ here