I've found that most of my regular partners really don't mind what I use against, as long as it's reasonably balanced. That's really a reflection of the crowd you play with though and obviously your mileage can vary. My advice would be just to ask. After a few friendly games I certainly wouldn't have a problem if you wanted to try something different. Helping to balance a list can be fun in its own right.
That being said, the SG Catachan list doesn't fall into the "reasonably balanced" category in most people's opinions

. Then again, if you don't power game it I'm sure it works well. Bringing it to a tourney would be tough, so you might be better off going with your SL list idea. Catachan's do have access to vehicles in limited numbers, so it's not that deviant from the fluff.
Let me know if the OH list interests you, I haven't put out the latest edition in the pretty format, but if someone's interested I can be persuaded. I've also finally got enough Catachan's to stop using proxies, they along with the DRM Jungle Troopers will make for a nice army.