You really did do a good job on that intergration. It actually might help the Secret Strike by giving it a larger airtank.
As for the small bit of tubing, you could either: mod your RF20 like mine (if you have one), then you'll get about a foot of tubing. PM me for the mod. Or, since I did that mod, I have about four inches left of clear (used the rest for my AT3K) and 6.75 inches of orange (it used to connect the pump to the Liquitron Guage on an AT3K). The orange tubing has a slightly (1/32") smaller ID, so pick which one would work best. I could put it in an envelope and mail it to you at no cost. If you reply to my post, I won't be able to get back to you until Sunday, maybe Monday, so sorry about that.
One last way to get the tubing is to go to a hardware store and search the place. That sometimes takes a bit of time and it's not free.